im not sure if anyone has already suggested this or maybe its not practical but here goes
over here in australia, foam tyres are a lot more common than rubber... well mostly anywayz (not sure if its the came for you guys)
i was only thinking the other day, when a set of foams gets too worn down for good use or too badly chunked or whatever reason, why not lathe them down to just the rim and drift on that???
its pretty much the same as pvc but with a bit more flex and its flat already...
just a thought, let me know if anyone's done this or is trying it...
Yokomo * HobbyWing * Sanwa