Physics following curve (idea)

Hello,

I’ve had a gripe with the blender physics and game engine, as the only way to get an object to interact with a path (e.g a ball rolling) is to create a housing for it (tracks, or guides). Wouldn’t it be simple to implement a follow curve for the physics, so the curve is not rendered just used to guide, and then a control (setting) for friction,

I appologise if this is not the correct area to be posting in, I tried searching for an official requests/ideas forum for blender dev, but could only find already documented requests.

here is a rather lame photoshop

http://www.pasteall.org/pic/show.php?id=23287