EVMS ( http://evms.sourceforge.net/ ) could do some of these things and shared the same vision as ZFS: "EVMS provide[d] a single, unified system for handling all of your storage management tasks." The memory is a bit fuzzy but I think it was a port/reimplementation from AIX or else IBM was involved. I think it died because it didn't integrate well into the kernel (like ZFS it smashed many layers into one).
Sendmail may be safely run set-user-id to root. -- Eric Allman, "Sendmail Installation Guide"