After a somewhat grueling process, I've gotten our multi-site installation to serve the pages relatively quickly - first, by turning off the 'Allow from All' directive in apache (note: this is NOT the Allow Override All directive that must be set for multisite), and secondly, by activating WP SuperCache.
The only issue I have left re speed, is the admin pages. Does SuperCache not affect these pages? Is there anything I can *tweak* to get these to move faster? My concern is, if developing a site with content management in mind (that is, someone else will maintain it while I go off and do other things), the slowness of the admin pages to respond is definitely going to get in the way. My other concern is that I haven't really sped up the process, I've just managed to put a couple of really big bandaids on the owie, and it's not yet healed!