My colleague Simon Lehmann has built the tracking framework Actracktive. Amongst others, it provides a Mac OS X and Linux application that allows tracking of touches and reacTIVision fiducial markers in optical tabletop setups. One could say Actractive does the same as, e.g., CCV but there are slight differences. For instance, Actracktive draws black patches over recognized fiducials in order to prevent detection of ‘phantom’ touches. There are a lot of those nifty tweaks in Actracktive, so maybe you want to give it a try.
However, Actracktive is actually an extensible framework to descriptively build CV processing graphs for nearly any purpose.
We use Actracktive in the Virttable in combination with Tuio AS3.