dude ,get a Disc hub flip it over and drill holes in your pulley gear thing using the old brake disc as a template. Then to get your belt line use washers under the surface of your pulley cog thing or adjust the axle in the hub a bit. Let me know how it works out.I'm sure you want have many problems.I think you can get away with using just a drill press.

I got the idea from http://www.63xc.com/jasom/milldisc.htm

as far as getting the belt on I would carefully cut the driveside dropout out with a smallish cutting wheel and develop some sort of bolt-on dropout that can removed with small bolts that mount/unmount it .uh, maybe. think about it man.You can figure some crazy $%#$ up .

Oh, yeah and good luck to you .