I haven't been tracking this regularly, but because you asked, I looked into it
It's actually a pretty common occurrence, there have been 65 such matches this season. If you'd like a list, I can make one, but I'm a little too lazy too do it unprompted
The biggest blowout that a player lost was Rui Machado losing in Estoril to Oscar Hernandez. Machado won 100 of 189 points (52.91%), but lost the match, 5-7, 6-1, 5-7.
This includes several notable matches (at least, notable to me):
AO R16 - Verdasco d. Murray 2-6, 6-1, 1-6, 6-3, 6-4 (Murray 138-137 Verdasco)
AO F - Nadal d. Federer 7-5, 3-6, 7-6(3), 3-6, 6-2 (Federer 158-153 Nadal)
Miami QF - Del Potro d. Nadal 6-4, 3-6, 7-6(3) (Nadal 101-99 Del Potro)
Madrid SF - Nadal d. Djokovic 3-6, 7-6(5), 7-6(9) (Djokovic 125-120 Nadal)
The pattern in this last one is a common way this happens: one player loses the opening set poorly, then wins the last two much closer.
The single most interesting example is probably Andreev d. Tsonga, IW R32. This was a straight sets win for Igor, 7-5, 6-4, but he won three less points than Tsonga.
Only one player has been involved in more than 3 of these matches this year, Juan Monaco. This includes his win over Murray in Rome, and a very interesting stretch in Buenos Aires: Monaco beat Nalbandian with fewer points in the semis, then lost to Robredo despite winning more points in the final.
Robredo and Florent Serra are the only players with three wins of this type, both are 3-0 in these matches. Robby Ginepri has been less lucky, as he is 0-3 in these circumstances.