Tiff and I double-trapped at Wayward Winds this year on my P19. Of course, since it never got over 4 knots all weekend, I was off the low side and she the high...I've done this several times since in light air.
Also, when the I-20's came out, several people experimented with trapping off the rear beam in heavy air/flat water downwind.
I've decided there are a lot more options of places to trap from (INTENTIONALLY) that I haven't explored yet. Thanks for a really fun thread!