I won't have 10.5 for a few months yet, but this is good to file away: 10 ways to get the most out of Quick Look.
I've always liked this kind of functionality. I started out first with Norton Utilities DOS NCView, then the DOS based Norton Commander with integrated NCView (F3 key I think). There was something similar to Windows 95 to, but I can't remember the name of it.
Funny how this sort of capability comes and goes. I hope it stays this time.