Server setup for multiple rails apps

i have a dedicated server running a bunch of small sites and blogs that
i’ve built in rails. currently i have apache+fcgi for everything which
is flaky at best. i would like to move away from fcgi if possible. i’ve
been looking at mongrel, and it seems to perform really well for high
traffic servers, but i’m thinking that those are servers running only a
few apps. if a mongrel cluster takes up about 128mb, i don’t think it
would be the best to run all 10 or so of my sites like that.

i’ve seen lots of environments that scale well for just a few apps on
one server, but i’m interested in the best for running a lot more apps