I am always amazed at the speed of LuaJIT, at least in these benchmarks:
http://shootout.alioth.debian.org/u32/code-used-time-used-sh...
It holds its own against scala and java -server with only a fraction of the code size (but only on 32 bit machines).
http://love2d.org/forums/viewtopic.php?f=4&t=2409
Seems to be somehow possible to get it working. It is not officially supported, though. I guess as luajit matures there is a decent possibility that it will be a supported option since games (even 2d) would benefit from the increased speed. OTOH portability of love2d would probably be decreased, too.