Ideally you would want a profile for each site, but you would have to manually set each new one up. But it sounds like you want to avoid that...
The easiest but least flexible way to do it would be to pop your _trackPageview with the full URL so it shows the subdomain instead of just path, in pages reports. But that puts all of your sites into a single profile, and there's no easy automated way to segment them (you can, but it's manual, esp since you have arbitrary domains popping up).
Alternatively if you don't wanna mess with having to change existing code, you can setup a domain prefix filter for your profile, to rewrite the page name to have domain prefix.. but that still gives you same problem as above. You can filter your reports to see
the different domains, but they won't be in aggregated buckets. You will have to basically export to excel and do some manual grouping/filtering there, would be easiest.