It looks like a really neat idea. I applaud the ingenuity and application.
However, many 'bare metal' coat hangers are galvanized, and thus may be coated with zinc or cadmium from what I understand. They don't look hot-dip galvanized like the hardware cloth you buy in buy at Osh (or weatherproof nails, rough feeling to them) but they may have a toxic coating to them nevertheless.
There was discussion a while ago about using galvanized coat hangers as pot supports, and whether the first few burns would be bad for you. That is where I picked this up, and a little further web research. If you are welding galvanized metal, you have to be cautious of zinc fumes which can scar your lungs. Cadmium is supposed to be worse.
If anybody had a definitive answer as to the coatings of coat hangers, it would be appreciated.
Alternative: Steel or titanium bike spokes?