is it possible to run multiple blog with one typo process?

is it possible to run multiple blog with one typo process? each rails
process takes 30-50MB memory, then several typo blogs takes quite a bit
resources. so how to modify typo to run multi blog with minimal
changes?

* each blog has own domain or subdomain name.
* each blog has own directory for its own DB and theme files.
* I know how to overwrite ActiveRecord connection() in a plugin
* but I don't know how to handle theme and layout for multi blogs.
overwrite layout() and detect domain name?

www.WuyaSea.com

Last time I checked, mephisto had better support for multi blogs.

from reading
http://mephisto.stikipad.com/help/show/HostingMultipleSites , it seems
that their support for multi site is an afterthought too.