Well how exactly would you accomplish that? You could put the tracker
on a location hidden service, that eliminates one exit node, however,
to connect with other hosts in the swarm, you need to be able to
connect to them... which means now, you have to have every bittorrent
client in the swarm ALSO running a location hidden service, lest you
need exit nodes to contact them.
I highly doubt any bittorrent client yet supports operating in this
manner. It would be very cool to see... but... there would be some
hurdles. (should each node in the swarm publish a public rendezvos
descriptor? If not a custom client would be needed to set them up and
distribute them via the tracker rather than the public directories).