Also, depending on how complicated it would be to do this, it might be useful for users (though I don't think I'd personally need it in the near future) to have some kind of control over how the length affects the clump length. Some way to switch (or fade, again depending on complexity) between "cutting" the hairs (where short clumps don't converge) and "de-growing" them (where short clumps converge).

Okay, so for whatever reason I can't edit the task description now, but I forgot to mention that the coloring on that cube is a visual representation of the vertex group.

Mac appears to be able to do it, too: http://www.wacomeng.com/mac/Developers%20Guide.htm

I looked through Wintab's documentation, and it would appear to have some support for detecting the pointing device: Wintab FAQ

My bad.