What I have heard is 10k for all first and second gen devices (ipod touch 1g, 2g iphone 2g, 3g) and then up to about 30k for the iphone 4 and therefore the ipad 1g. I am sure you could go with about 20k for the iphone 3gs. However, with the ipad 2g and, hopefully in september the iphone 5, I bet you could get up to 60k. This is just a guess, but provided the ipad 2g is supposed to be much faster than the ipad 1g, it should be possible to get around 60k.

I don't know, but try looking up what graphics processor the iPad uses and see if you can find a good polycount for something with roughly the same capabilities.