My group of friends rotates thru things pretty quickly so I don't know how long this Battletech craze for them will last. That being said..
I was considering a Mad Dog III for fire support or a Viking II, and definetly a Tyr for vehicle support, maybe with an Epona as well. I have to see how large of a force we want to play with.
If I can convince him a Trinary that would be awesome: running a Command Star, Support Star, and Harassment Star. If it's just a Star then most likely A mech Lance and BA Point.