His only comeback from 2 sets to love down that I recall is against Kendrick at Wimbledon in 2006.
Roger has done it a few times for sure, one of them against Nadal in Miami (2005).
I think Nadal's record being down two sets to love is interesting in the sense that he's a mental giant and known to never give up, yet he's done it only once, but the explanation is actually very simple: Most two sets to love comebacks by top players are against inferior opposition. In other words, if you're down 2 sets to love to Fedal or Djokovic, you're probably not winning the match. In general, Nadal just won't lose the first two sets to nobodies, and the rare occasions in which he's down two sets, it's the opponents on fire and he just can't make a comeback. I guess the closest thing he's done is Muller at Wimbledon last year.