WTB: Beginner Uni 20" or maybe 24"

One of my friends wants to get a unicycle, so he asked me if I would see if there were any used ones he might like. he was thinking something like a CX or one of those suns. I think he would like a 20 but a 24 might be ok.

How about this Schwinn? http://www.unicyclist.com/forums/showthread.php?t=54333 It’s tougher than CX’s.