I see that BPS is compatible with Multisite. But does it also work with Domain Mapping.
If it relies on .htaccess files, this is an important question. The wp root htaccess is ignored when when a member site is accessed by its own domain. As far as I can tell not even placing htaccess files in the blogs.dir or blogs.dir/#/ directories had any effect at all when files are being accessed by a mapped domain name rather than a subdirectory or subdomain.