They sell coil wire, so you can roll/wrap your own coils, at radioshack. I have a zipzap chassis with some coils in it. The only catch is that I don't know if these coils work. I got this chassis from airbob20, along with some other parts. If you want the chassis/coils, shoot me an email and I'll send it out to you.
Maybe, in return, you can make some of those brass rings for a full size wheel mod for me
edit: I could test the coils out for you but I probably won't be able to get to it until late new years day. (I'm at work now and will be going out after work). Also, you don't have to make those brass rings for me if you don't want to. You still can have the coils.