Yeah the cast wheels is probably a non starter, but a good forged wheel like a Weld should be doable right?
I'd talk to a few pro's before going ahead. I'd think forged would be do-able, but I've never welded forged aluminum either. I have welded cast aluminum, and based on that I would never weld a cast wheel even a little. I just don't know enough about forged aluminum, other than it's strong as hell. I would worry about taking the temper out of the material with that much welding. AL is finicky...
I certified on a 6061 AL unlimited thickness MIG procedure many years ago. The biggest issue was overheating the material and taking the temper out of it. So easy to do, and no visual indication that you are overheating the material. On something as large as a rim I think it would probably be easier to manage the overall temp of the rim, but again I'd rather defer to a pro that has some more current experience than I do.