Ivan,
What are the possible bad consequences of enabling your cache plugin on several sub-sites under a multisite WP installation? Would it totally break?
The technique of DB caching seems superior to page caching but W3 Total Cache (which has that) is just WAY too complicated and some of my pages would not refresh at all, even with ctrl-F5. So I'm wanting yours to work since Caching is one of those system utilities that should just work quietly in the background so we humans can get on with OUR work and not babysit it.
Good luck,
Ron