Does anyone offer a master electrician test other than the IBEW?

Volts;
the test is 'proctored' by various private biz, i think it's the NAI ( National Assessment Institute) in some of New England.

I don't know where your from but many states issue licenses. I got mine from WV. The state of PA does not offer a license other than through the IBEW.

Check with your State Fire Marshal's Office or check on the web.

Volts, try Here

Our IBEW LU doesn't give "master electrician" exams (Allentown, PA). But the various cities and townships do. I took the one offered by my city, which happened to be the Experior exam in that link Sparky posted. Here is a link to some state requirements.

licensing