I may have to look in to this later down the road sometime. I'm not sure if what we have is really 40", but I think it might be. The only real problem with it is that the one really long bolt that goes up from the middle of the dish mount to the top part busted - that happens when you have two bolts interlocked like that and you turn the one on the side too tightly, causing the one going up the middle to bend and then snap... also would need to rig a mount and get a Cband or Cband+Ku LNB... for now I'll live with KU band... it does sound like a nice little project for sometime way down the road though, assuming that I can get enough of the metal heaviness of of the P* so that the SG2100 would hold it.
Pstar dishs are nice dishs, Give it a shot for cband and see what happens. If you dont have any luck on c band I would set it up anyways and use it fixed on g10 or other satellite of your choice.
If you want to accomplish the C/Ku Band with a smaller dish then try the phased arrays that they have out. I seen some threads on this a while back. Some looked like a bubble if I recall correctly. Have not heard about them since.