I don't know of any distro that comes with one either. Instead of trying to find one with a torrent program already built in, why don't you just learn how to install apps in Linux? Trust me, it's a lot easier and faster than trying to find a Xbox Linux distro with a BT client in it already.....
If you're using Gentoox Home, just open a terminal and type
CODE
emerge azureus
or
CODE
emerge Azureus
if the first one doesn't work.
I haven't used Xebian in a long time so I may not be exactly correct, but to install apps in xebian, you just open a terminal and type
CODE
apt-get install azureus
Note: You don't have to use Azureus, you can use any other BT client, provided that one is available for linux and it's hosted on the gentoo emerge servers, or the debian package servers. I just used Azureus as an example because I know it actualy runs find under Gentoox, although it's a bit of a memory hog.
Note: If you decide to go with Gentoox (which I recommend you do), you'll need to do
CODE
emerge sync
before you try to install any new software via emerge. <