Many, if not most, of us have at one point designed the perfect set of mechs/omnimechs all using the same engine. The 240 standard, 300 Light and 300XL (usually but not always Clan) are popular options, but I've seen others. Often people try to limit the amount of other equipment types as well. Sometimes people are nice enough to themselves to give themselves more than one engine and make ~10 mechs instead of the normal spread of 4-5. Sometimes vehicles and ASFs are included. Whatever the exact restrictions you use, the "new model army" that slims down all the chaotic Succession Wars fragmentation/Star League bloat/Clan insanity to something more sensible is a common dream.
Your challenge, should you choose to accept it, is the screw that up. Put yourself in the place of a minor mech manufacturer in a nation where a plan like this has been adopted who are on the verge of being forced to licence designs from the 1-2 big mech manufacturers that have won the contacts to design the "Project XXX Engine" designs or only build for export. Your objective is design a mech that has capabilities destinct enough from anything the standard line of omnis can do that your nations military actually wants to buy it. The ultimate result may ultimately be determined by politics and lobbying, but you have to make something obviously destinct to give your supporters something to argue for.
Techbase is whichever techbase your favourite "new body army" uses, but without any of the restriction you previously put on yourself and perhaps plus a single proprietary experimental tech. Assume that engine(s) that have been picked for the project are unavailable to you. Feel free to complicate someone else's logistics if you have never had (or never given into) the temptation to make one of these. Bonus points for appropriate fluff on exactly how the mech ended up being accepted into service despite the original plan.
