Well, a few more hours and a few more crashes with 7.5 xstream but I suspect that some of the crashes may possibly be the fault of the PLE edition as opposed to the purchased edition.

It is working within C4d R11.  The 3D Connexion Space Pilot is working as well and IPP seems to experience no conflict with the xtream plug.  Using C4d's renderer is relatively quick (I haven't tried VRay as of yet, although it is next on my list of tests for the Vue C4d combo), even with a complex scene containing a mixture of Vue, Poser and C4d elements.  Animation works as it should.

If I can somehow wrap my head around the fact that crashes will be inevitable until, or perhaps if and when, Mac stability issues have been addressed and resolved, I may decide to purchase the software but for the time being I will continue to test the program.