I've just bought one of these:
Buy them here:
http://cgi.ebay.co.uk/B-N-I-B-MOTOCROSS-JACK-UP-STAND-HIGH-QUALITY-HONDA-CRF_W0QQitemZ260085798355QQihZ016QQcategoryZ122304QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
£19.99 plus a tenner for prompt delivery. Decent bit of kit - all metal and pretty sturdy. Also comes apart quickly for storage if you need.
It has a metal top plate with a rubber cover which is pretty strong, and avoids the usual cheapo problem of plywood which delams pretty rapidly in the wet.
Lifts my XR400 with ease and holds it dead steady. Only down side is that the handle doesnt have a locking pin so you need to make sure you don't trip over it and dump the bike on the ground, but it's not a problem in practice.
Thoroughly recommended for the money.
LC