Ugh. Sorry to bother you all. After a little (very little, actually) searching on dejanews I came across the answer: swing just doesn't work well when tunneling over secure shell. When I'd done my earlier performance checks, I'd been using straight awt. Read somewhere that swing components aren't very well supported in X yet, so it requires a lot more data to be sent over and used, something in that arena.
Thanks anyways, -Charles
