Let's see here is what i have seen floating around here
ISS Interior, ISS arms, shutdown procedures, better (i.e. realistic) shuttle models and textures, old shuttle avionics for the older missions, 51L and 107, active mid-deck(?), chase planes, MON2 active, and Mir. Oh yea and all of the missions not yet modeled...
Ya'll don't want much do ya?
I would be happy with the age appropriate avionics and one Mir mission (preferably STS-71 or 91). The rest falls into the "If I had a million dollars" or "would be nice" columns.