I wouldn't go so far as to say he deliberately tanked against Verdasco, but I would agree that he almost certainly didn't put his heart and soul into winning that match. I don't think he was devastated by that loss because he was so p1ssed off with the surface that he was glad to get away. His threat never to play Madrid again on that surface was quite open and blatant. I think he used his early exit as backup for his position. After all, if he had gone on to win the tournament, it would hardly have lent as much weight to his arguments!
Of course, Djokovic then conveniently did the same by going out early to Tipsarevic, another player who, like Verdasco, is normally easy pickings for Nadal and Djokovic respectively. It was probably no coincidence that Djokovic was as anti-blue clay as Nadal. Both of them got away with it and put enough pressure on the ATP to force Tiriac to restore the original red clay surface.
Top player power, eh!