To second agnaramasi's earlier post that this is possible I got the deluge daemon up and running on my DS211 at the weekend. It was a bit of a faff but certainly worth it as the thin client/server setup is streets ahead of the web interface.
I haven't got the precise steps written down but they go something like the following.
Install the following with ipkg packages: coreutils python26 py26-beaker py26-mako py26-openssl py26-setuptools py26-simplejson py26-twisted py26-zope-interface.
It's worth noting that I had to manually pull down wget-ssl and remove wget and install it in it's place to satisfy the coreutils dependency. You may prefer to install the necessary build packages separately.
As you can see I chose to compile against python 2.6 (2.5 may well work but I didn't try). If you're using 2.6 the ipkg provided python 2.6 distutils config (/opt/lib/python2.6/distutils/distutils.cfg) appears to point at the python 2.5 site packages directory after installation so that needs correcting first.
Download and compile boost with the date-time, filesystem, boost-iostreams and python libraries making sure to point the config at the python binary of your choosing. I chose to install to /opt though /opt/local (which I think was the default) will probably work too. I can't confirm whether the boost libraries in ipkg work or not as I went straight down the compile from source route, you might want to give them a shot first as it saves a bit of effort and compile time. For reference 1.45.0 was the latest version when I did this and worked fine for me (see build instructions at
http://www.boost.org/doc/libs/1_46_0/more/getting_started/unix-variants.html#easy-build-and-install).
Next up, grab the libtorrent-rasterbar source and run the steps for building with autotools at
http://www.rasterbar.com/products/libtorrent/building.html#building-with-autotools to build a release build of the library. Don't forget to build the python binding using setup.py as outlined at
http://www.rasterbar.com/products/libtorrent/python_binding.html#building-using-setup-py. Again I chose to install to /opt but /opt/local ought to work too.
I found the ipkg provided pthreads library was broken so if you find the libtorrent configure above fails to find/link against pthreads (and subsequently find the boost libraries) then follow the resolution at
http://forum.synology.com/enu/viewtopic.php?f=90&t=30132&p=119287&hilit=pthread#p119287. This had me stumped for some time as the configure output/log doesn't suggest that the failure to link is actually a problem and only bails when trying to find the boost libraries.
Once that lot's done then you should be able to download the deluge source and build with no problems. If it starts trying to build the bundled libtorrent library then there's something wrong with the libtorrent-rasterbar build/installation above which you'll need to check.
I hope these pointers help others get this up and running.
Cheers,
Trev