Can newer releases of a distro be run in a chroot from within an older release? What problems will occur?

I'm running Slackware 12.2, mostly because that was the last release supporting KDE 3.5.10. I run my Trinity builds in a chroot.

I would like to start Trinity build testing for the most recent Slackware release.

I can run newer releases in a virtual machine, but I find virtual machines much slower than the chroot.

Thanks.

Darrell