Oh man, how did I only just notice this thread?!
Anything you guys fancy organising I'd deffinitely be up for, time and money providing.
As for social games that are a little less plot intense, we could just proxy some of the battles already mentioned in the Heresy series so far... for example, Marines versus Marines could represent the battle at the Precentor's Palace on Istvaan III or the Dropsite Massacre. If we have 'Nid or Ork players, then the Murder campaign, or Ullanor respectively.
This gives us a rigid start/end situation where everyone already knows the outcome, but gives us the opportunity to convert some cool stuff, immortalise our favorite characters in metal and plastic, and crank some really fun and contextually appropriate games. You know, all the stuff us hobbyists live and breathe for.
Just an idea I thought I'd throw out.