Bug-tracking tools that handle branch/merge/etc

Partly referring back to the discussion last June (http://article.gmane.org/gmane.comp.version-control.git/49734)... has there been any developments in the area of a BTS that can grok GIT in a sane way?

Main concept I see as important for a BTS grokking git:
 * Capability of following branches/merges in a way that
   you can see a list of bugs that affect a branch at any point
   in time.

Niceties include:
 * The ability to 'distribute' this so bug tracking is as disconnected
   as coding itself (great for airplane-trip coding sessions)
 * Ability to watch incoming commits (suppose the BTS can 'pull' from
   various sources on occasion) for messages marking a bug as
   in-progress/fixed/re-opened/etc.
 * Local-application GUI integration... ex: gitk/git-gui + BT