We are looking at putting together a few Reprap Prusas. This guy's kits look nice, but $825/kit seems a little high to me.
MakerGear.com - Prusa 3D Printer
It does have the advantage of already having metal bushings/bearings, which seems to be one of the first incremental improvements most people make to their machines.
Our main end goal here is to determine if there is a way to produce the machines cheaply enough that they could be sold fully or mostly assembled as educational toys. Maybe somewhere around the $300 mark.
Another goal would be to reduce the delivery time - many reprap vendors seem to have a lead time of a month or more.