One of the best matches I watched at Fight to Win 136 was Edwin Najmi vs Johnny Tama.
Edwin hit a dirty toreando pass to reverse triangle and basically rode out almost the entire match with Tama trapped in this position. Judo guys use this as a turnover to pin from turtle, and Tama's reaction to the pass put him in a similar position, so Najmi was able to go for this unorthodox entry to the triangle.
It's not that common a move in jiu-jitsu. It is used to great effect in judo, albeit moreso as a pin than submission. The reverse triangle definitely functions as a submission, but it's not easy to apply – as Najmi found out.
There's no better person to explain the finishing details of this technique like the man himself, so I've included Edwin's own video where he teaches the position. Enjoy.