I have started testing this with Workstation 8.

VMware Workstation no longer crashes the kernel with the Sennheiser USB headset when using Workstation 8.0.1 and Fedora 14.  I have also tested with Workstation 8.0.1 and Ubuntu 11.04, and receive the same results.  Given those combinations, after removing the blacklist and loading  snd-usb-audio, I can once again toggle the device between a Guest and  the Host without crashing the kernel.

I have not yet tested the UVC, but am hopeful that Workstation 8 has resolved the problem.  More testing as time permits.