Building tools

ooh, look...

Creating 3D Tools with MFC:

http://www.gamedev.net/reference/articles/article1358.asp

It's pretty old, where "Game tools have long been overlooked as an important piece of the development process....." still seems to apply.

It's a fast and breezy intro where Author Joe Houston concludes "Through experience and code reuse new applications can be written in mere hours". From there it usually starts getting more complex - and probably so much so that suggested follow-up articles would have perhaps not have been as much fun to produce as this one. Interestingly as this subject progresses you find many of the other specialised 3D topics ( that abound here) start coming into play.

An updated version using c#/directx or c++ .net/(opengl or directx) would be even breezer to produce with forms!

There are bits and pieces of related info around the net (Code Project comes to mind) that may become useful to you. But it seems as though your mainly on your own (which is an interseting challenge!). I have dabbled with tool type stuff for a while, so if there are any specific questions you may have, I might be able to help.

ok..I just noticed you are aware of said article

Game Engine Toolset Development
I haven't read this one myself, but it has come highly recommended, and is by gamedev's own gwihlidal.

Not entirely what you want i'm guessing, but might provide a starting point. I think Tao has a different GL initialisation now - not sure....