Well, here's Euler14 in Lua for a start: http://lua-users.org/lists/lua-l/2010-09/msg00568.html

But obviously for a proper comparison of the runtimes the benchmarks need to be implemented the 'same way' and not simply yield the 'same result'.

Not at all, I'm just asking for comments from anybody who has experience with both. I used to use Python quite a bit, but switched to Lua a few years ago and PyPy really hasn't been on my radar.