Although I've given up on resolving the problem and backed the site out of WPMU, primarily to eliminate WPMU as a cluprit for Wishlist Member plugin issues. It could be that the lack of a dropdown is to BlueHost.
I did speak with BlueHost after installing WPMU and determining that wildcard DNS were not working as they should. Technical support explained that this feature and WPMU as a 3rd party application were not supported in a shared hosting environment.
My client would not consider changing hosts or securing a VPS, however, so we went forward with the caveats. It was a long road, but three separate sites are up and running perfectly, even without the expansion possibilities that WPMU offers.