Deluge
I applied the suggested PPA but it appeared to have no effect.
After adding the PPA apt-get tells me my version of libtorrent-rasterbar6 is up to date (still 0.15.10).
I noticed these packages have only been built for amd64 and i386, not armhf.
After searching launchpad (didn't know that existed, thanks) I found https://launchpad.net/ubuntu/saucy/armh ... 1-1ubuntu1
Its compiled for armhf and is version 0.16.11 however it depends on libboost-system1.53.0 and libc6 (>= 2.17). dpkg tells me the Pi doesnt have these and so it wont install. Sigh.
Downloaded libboost from here. Installed fine.
Downloaded libc from here. dpkg encounters 3 segfaults while trying to install. Sigh.
Tried libc 2.15 and got the same result. The Pi has libc 2.13 which apparently isn't enough.
I followed instructions here to try and upgrade libc. All seemed to work well, dependencies were identified and installed but it ultimately didn't work because the same 3 segfaults occurred while installing libc.
It would seem libtorrent >0.15.11 wasn't meant to be on my Pi.
Next step is to try all this again from a cleaner SD card image (one taken before all this started). Hopefully a cleaner slate will give me better luck.