George,

I think your plan is great. I don't have your difficulties, however, as a life long die maker and woodworker I see no problem to you operating a lathe.
The secret is getting the lathe close enough to you. I suggest:

1. Using a mini or midi lathe.

2. Mounting it onto a custom made table that will position it in and just above your lap. This will necessitate...

3. Using a chair with no arms while turning.

If you can do these three things then I believe there is no reason that you can't become an accomplished metal and/or wood turner as good as any.

Keep me posted on your plans and If I can assist in the construction of any of the above, let me know.

Bob