I suggest sidestepping the problem completely. Consider using blender as an extremely powerful editor.

My suggestion too.
Or a plugin to any other editor your 3D guy(s) like to use.

Writing UI:s is a lot messier then one might think, specially 3d stuff, and you can easily spend more time on this then on your engine.
Also, not having to switch program after making your models is a nice productivity boost, and no need to learn (and invent) a new UI