Mark,
that's right another layer that could be exploited. I'm running production w/ the previous Pound 1.6 current (no longer available from Apsis as it has been replaced w/ a newer version). I haven't tried this new version.
I can't give you hard data points but as a comparison I'm running 3 AOLserver instances on a single processor w/ 640 Mb quite comfortably. Mind you all these sites are small sites. The Code Mill (http://www.thecodemill.biz) gets the most hists. Nothing to write home about though.
Maybe that others who provide virtual hosting can give more detailed information.
/Bart