The issue is not so much that the low-level drivers don't exist (although they are unmaintained afaik), but rather that there is almost no software available for Linux which supports real multitouch gestures, and certainly none (I'd love to be proven wrong about this) which supports finger-tracking as OS X does.

I rely on it heavily for window management and navigation, and the Linux community is sorely lacking in this department atm.

I have never really looked into it, but searching the archlinux aur for multitouch a few things come up:

easystroke-mt - Use mouse and screen multitouch gestures to initiate commands and hotkeys.

touchegg - Multitouch gesture recognizer

Obviously I can't tell how well those work and whether there are better projects...