Hi Uncle Al,
You've probably got your devil contained by now. But it sounds like the materials aren't exactly cheap..
Have you looked into Coesite? I've read that it is resistant to hot hydrofluoric acid.
How about a thin CVD coating of diamond on a cheap silicon carbide crucible?
Is devil solvent electrically conducting? Maybe you could use a levitaion melting apparatus. Then again, if it has any vapor pressure at all, this won't do.
-Scott