I mentioned this in another message, but here goes. I recently purchased
an item which I'd like to display in a glass case, similar to an
old-style museum glass case. It'd be a rectangular cube, two feet wide,
maybe ten inches deep and high. The sides would be glass, and the edges
would be a hardwood like oak or mahogany. It'd be like a Barrister
Bookcase unit with glass sides.

The problem I have is the joinery of the wood. At each corner, I'd have
three pieces meeting. And I'd like to keep these wood edges fairly
narrow, so as not to overwhelm the glass or the contents of the case.

So I'm having a time trying to figure out how to make the corners
"meet." I don't think cutting 45-degree angles and gluing would be the
best method, but I can't think of how other methods (mortises, floating
tenons) could be done without requiring fairly thick edges.

I haven't decided on other strategies, like having a higned lid or front
or whatever, but I'd like to know how this three-way joinery can be
done. Are there any web-available ilustrations which I could consult?
Magazine articles (just the reference'd be fine)? Recommended books?