Only problem is that it pegs out the CPU at around 100% and is markedly slower than it should be. (Maxed out at 30KB/s over loopback...)
Which means I missed the Extend Firefox contest. Fooey.
However, now I'm moving on from the, uh, "test implementation" to an implementation written in C++ using XPCOM. Hopefully that'll be capable of creating a working BitTorrent client that doesn't peg the CPU and downloads at a sane speed.