I think the key issue is that there is no software native to the mac that has a version that runs on windows (and communicates between the two), that I know of.

If you are willing to (and the mac is a powerful enough laptop) you could run windows on it and get two copies of keyclone one for each machine.

If you are only dual boxing then it might be better just running two versions on the mac using the mac key broadcaster, which should be listed on the wiki.