Here's a start: http://github.com/nealrichter/tokyotyrant_rsshack
I've attempted to do this myself and have not had the time to finish or fully test it. I've asked Mikio for feedback/help finishing this and he's been nearly silent on the request.
At the moment we (myself, Sam Tingleff and Mike Dierken) work around this issue by continuing to play with various parameter TC settings and restarting the daemon when the memory usage grows beyond a comfort level.
I'm a C coder and have hacked the internals of BerkeleyDB in the past, so can help review code, trade ideas, etc. We (as a team) don't have the time to work on this at the moment.
If you are interested contact me! We've got a few other ideas for TT enhancements as well...