I'd wish to see Hercs from the legendary game MissionForce: Cyberstorm 
I know some of them move on four or six legs and have weapons placed a bit ridiculously, but some of them could be used such as the Giant, Reaper, Hades, Juggernaut and Remora ..
and if you guys want to take a look of them here's a couple of links: Hercs & Cybrids
Don't forget HERCs from StarSiege. Same universe, but, diff chassis and otherwise. I'd love to see em in, but their higher tech would just make them overpowered.
Plus this is battletech, not metaltech/starsiege.
But what i was thinking about adding Starsiege and/or Cyberstorm HERCs, was that their weapons and armor would be modified to a Mechwarrior friendly, for example the Giant; it can be used as a ballistic support with Long Tom, LBX, Autocannons etc. or it's weapons could be converted to Omni-slots for different variants ..
Another example would be Remora, it can act as a fast moving Scout/Anti-tank/Anti-infantry 'Mech, with a few small/medium lasers and gatling guns ..
i have lots of ideas about how to make these HERCs suitable for Mechwarrior .. but i'll save them for some other time
