Transcribing with TextMate is surprisingly easy. All it takes is a new bundle with two commands, one that takes you back by three seconds, and one that pauses or plays.
#!/usr/bin/env osascript
tell application "iTunes"
set currTime to get player position
if currTime < 3 then
set currSkip to 0
else
set currSkip to currTime - 3
end if
set player position to currSkip
end tell
And here is play pause:
#!/usr/bin/env osascript
tell application "iTunes"
playpause
end tell