This is just one of those things I'm going to throw out there, because occasionally I get people that ask how exactly to build a unit in a universe as crazy in depth as the BattleTech one. For the record, I'm basing this purely on my own interpretation of the BattleTech universe and the factions contained within. As with "Building a MechWarrior," I'll break this down into three sections.
1) Inner Sphere/Periphery - Because you're looking at an established affiliation here, you have a wealth of resources on canon units and a literal ton of ideas for a non-canon unit. That being said, your affiliation is the first place you want to start. Look at the history, the geography and the feel of each of the factions. Do you like the various regions of the Free Worlds League or the Japanese flavor of the Draconis Combine? Want to be on the fringes with the Romanesque Marian Hegemony or a diehard Capellan Confederation traditionalist? Once you know what faction speaks to you, the next thing you need to know is what units that faction has access to. This is one of the toughest points because there are hundreds of miniatures out there and many of them are just pretty damned sweet, not to mention there is the overwhelming temptation to use dozens of Clantech designs in your Inner Sphere or Periphery force. While in some cases that might make sense, especially if you're the type of player that has to have the absolute biggest guns despite the lack of logic or even playability (see earlier posts and the Core Rules for weight modifiers, etc), most players will be hindered by having pieces they're never able to really use.
Now, I am in no way telling you what to spend your hard earned money on. If you build it, someone will probably play against it. However, thinking logically, if you build a Sword of Light company (one of the most iconic Draconis Combine regiments), and out of 12 'Mechs, 7 are Clan designs, 3 are Federated Suns designs (because the Combine has fought the Suns a lot and you're using the "salvage logic"), 1 is an Inner Sphere general and the final is something the Combine actually produces, you're not really fielding much of an iconic Drac reg. It's your choice but when it comes time for us to drop, people might look at you weird if your lance of Dracs is a Feddie Sagittaire, two Clan Masakari/Warhawks and a Lyran Stiletto. The best way to decide what "foreign" pieces to use and especially what Clantech to use/avoid is to look at your faction's war record; who they have fought, how long ago was it, how did they do, etc.
In place of that, my recommendation is (as usual) a maximum of one or two Clan 'Mechs per four Inner Sphere lances, and one max "out of faction" design per lance. My above example of the Sword of Light company could look something like the following;
2 x Akuma (Drac)
1 x Nobori-nin (Clan Nova Cat)
1 x No Dachi (Drac)
1 x Avatar (Drac)
2 x Black Hawk KU (Drac)
1 x Wolverine (General)
1 x Raptor (Drac)
1 x Jenner (Drac)
1 x Panther (Drac)
1 x Raven (Capellan Confederation)
Now, this is just an example and not necessarily an optimized company, but you end up with 5 OmniMechs, but only one of them Clantech and a good, hard-hitting force that is very heavily Draconis Combine.
2) Mercenary - There are dozens and dozens of established mercenary units in the BattleTech universe but this is really where a non-canon approach is great. You can basically take a disparate collection of miniatures and form it into something that works not only for you but for everyone you play with. You'll still want to think of a faction that you like, for the purposes of your history and command staff. Where are they from? Does their training in certain faction tactics or preferences color the new unit's build? It's also important because you'll want to have probably half the unit (at least) made up of that faction's 'Mechs. As a mercenary, you have to be able to support your MechWarriors in the field and if you have 'Mechs from every part of the universe in a company, logistics become a pain. While that matters more in a campaign sense, don't underestimate the disadvantage of 12 different range/movement profiles. Having a Heavy PPC as a prime weapon on one 'Mech, a Heavy Gauss Rifle on another, an ERPPC on a third, an Ultra AC/20 on a fourth, etc can give you fluid tactics but can limit how well your pieces work together. Clantech should really be limited even more here, unless you're Wolf's Dragoons. And if you are, hey, good luck in the Jihad guys.
There is mucho fun to be had naming and back-storying your mercs as well. As my example here, I'll use "Duke's Deviants," named for Duke John Sandoval-Richards, formerly of the AFFS;
1 x Templar (Feddie)
1 x Enforcer III (Feddie)
1 x Stealth (Feddie)
1 x Fireball (Feddie)
1 x Thanatos (Feddie)
1 x Hatchetman (Feddie)
1 x Fafnir (Lyran Alliance)
1 x Banshee (Lyran Alliance)
1 x Koshi/Mist Lynx (Clan Smoke Jaguar)
1 x Thunderbolt (General)
1 x Warhammer (General)
1 x Griffin (General)
Again, not necessarily optimized, but a very decent unit with a couple Omnis, a good Clan scout 'Mech and a range of weapon combos that could offer serious fun.
3) Clan - Building a Clan force is at once the easiest and the potentially most difficult type to construct. On the one hand, most of the best Clan 'Mechs are listed as "Clan general" and even the more specialized ones are found in several Clans at once. On the other hand, each Clan has a slightly different flavor, approaches the concept of honorable combat differently and can get confusing if you've never paid much attention to them before. As of 3067, there are 15 or so Clans, but only 7 have any real presence in the Inner Sphere - Jade Falcon, Wolf, Ghost Bear, Nova Cat, Wolf in Exile, Diamond Shark and Snow Raven. In canon, the Hell's Horses will form the eighth after 3073 and (excluding the Wolves in Exile and Nova Cats) will be a member of the "Council of Six" after the Jihad. However, because I'm a huge Blood Spirit player, for non-canon campaigns, the Spirits will be forming their own OZ instead of the Horses. That still leaves a large amount of "Clan flavors" for a new player to jump into. Once you know what Clan you like the most, then you have to look at the size of the force you want to build, the function and whether it is heavily front line or second line. Front line forces use more OmniMechs than second line, which tend to favor "IIC" and standard BattleMech designs. The exception to that is the Blood Spirits who make heavy use of the Blood Kite 'Mech in front and secondline forces.
For my example here, I'm going to use a very generic Clan Wolf Alpha Galaxy force.
3 x Mad Cat/Timber Wolf
1 x Daishi/Dire Wolf
1 x Sun Cobra
2 x Puma/Adder
1 x Linebacker
1 x Fenris/Ice Ferret
1 x Lobo
5 x points (hex bases) of Elemental Infantry
This gives you a combined-arms Trinary, the Clan version of a company and will definitely keep your opponent's head ringin' with 8 OmniMechs and two fairly decent standard 'Mechs
And it would be remiss of me not to mention that you could easily go to www.CamoSpecs.com and figure out a unit you'd like to play just by paint schemes. Just make sure you don't bite off too much there 'cause man, can some of the canon schemes be tough to paint...
