"On this end, one of the challenges with a small development group such as ours, is that adopting hardware support potentially increases our risk of incompatibilities."

This is true and a definite problem. I think the easiest way is to support it in a non critical way.

For instance, Max will let you enable OpenGL and Direct3D shading in a view port - but it does not consider such views as critical or definitive of what the final output will look like. The "active shade" window in Max is a good example - if you turn it on and your hardware supports it than all is well. If not then you leave it off. No harm done.

I would be very interested in seeing what happens if you guys just dumped the poser scene onto the Direct3D library. Let it handle the details of optimizing for a specific card/driver - it's what it does (it's all it does! to paraphrase Terminator 1).

On the Mac side QuickDraw3D is similar.

It might be an eye opening hack :)