how do people play with different versions of DBSD on the same system?

[Bob Bagwill]

How are people playing with different versions of DBSD on the same system?
Do you install them on separate disks? Separate slices? Separate partitions?
If you want to avoid having separate /etc's, /var's, and /home's, what's the most elegant
way to do it?
When superVFS is in place, would we be able to have a /release, /preview, /development,
and mount them over / at boot-time?
--
Bob Bagwill