its doable, but if you don't have acess to free or cheap machine work it isn't worth it. just did a set for my xr650r. about eight hours of machining. do a search on cast wheels.
the only machining i did on my front was to recess the rotor in a bit to give some room for my caliper. all i had to do after that was cut up some spacers. the rear was obviously the hardest to do and even more so because i kept the cush drive functional. a lot of the other posts of f2 wheels have the cushdrives welded onto the wheel but i wasnt too fond of that idea.