I've actually experienced this before several times. My most recent attempts to use it in battle have been pretty successful.
The goal to perfecting this tactic is making M2's teleport path collide with the edge at an angle approaching horizontal. Do your trig, it's fairly simple. You're trying to appear as low to the stage as you can.
......M2
..../,..............
M2..\
.......\
My general M2 recovery mindgame scheme:
Fastfall, Doublejump, Tele up sweetspot x ?
Fastfall, Doublejump, "Ledgecancelled Tele", Roll
If you can get the timing perfectly, this has NO LAG allowing you to do pretty much anything immediately afterwards.
Nice job on capturing this on video Airo. I beleive this technique is easily fast enough to be used against decent human opponents.