I'm currently running 9.3.1sp, 10.0sp5, 10.1sp1, and 10.2.0 on SQL-Server,
10.2.0 on Oracle, and 10.2.0 on PostgreSQL on my W7 laptop...
it's possible to run them all at the same time
... I've never had more than 4Gb RAM on my toaster ovens, so I've never been able to get Oracle 8i, 9i, and 11g running at the same time
Do you have a white paper on this?
What about the toast?