None at all :) The closest we have is that we want this to be part of the 1.0 release, and we want to have the 1.0 release before the Web Rebels conference may 24th.
You can use phantom today, though. Any browser works [1], and phantom is a browser, so just open /capture in phantom and you're good to go. The integration we want to have is basically just to automatically start a server and capture phantom in it when you type "buster test", not to make phantom actually work with buster server, since it already does.
[1] Currently we use two connections in the browser for talking to our buster server, this clogs IE7 and other old browsers with a 2 concurrenct connections limit.