linux-only jail possible?

[John Nielsen]

Has anyone tried to run a jail containing only Linux binaries? I need a 
lightweight VM-ish solution to run an arbitrary number of test/dev/demo 
servers (apache + python mostly) but would like it to be reasonably close to 
the "real" servers (running Linux) in terms of software installation and 
maintenance, etc. (Moving the whole show over to FreeBSD is a battle for 
another day..)

Aside from the logistics of actually making this work, are there any known 
or obvious show-stoppers/gotchas/pitfalls/etc?

Ideally yum and rc+init.d would work normally, though I expect a bit of 
startup hackery may be necessary (as well as hand-extracting a bunch of 
RPM's to bootstrap the first jail).

If you have attempted something like this I'd love to hear from you.

Thanks!

JN