pi board support

I have a small perpex case that the pi should just squeeze into. I am looking for a material that could be used as a pad that the pi board could rest on to avoid damaging the case or the boards lower pins. Something like a foam pad at least as thick as the sd card holder that I could cut to the size of the board minus the sd card holder. What would be suitable electrically? Anything from RS or maplin? thanks

If you have a Tesco nearby (and lets face it if you're in the UK you probably do..) go to the 97p specials and look for a packet of felt pads, there's a sheet of 4 large ones in it that would form a perfect base for your Pi.