Real Madrid have cropped up a lot in the reports and i seem to recall several (non-spanish) international players leaving the club shortly after the whole shebang kicked off, one being goldenballs. his name was certainly bandied about at that time, as was a marathon runner of considerable fame who had a spectacular loss of form shortly afterwards.
You can hardly claim that Beckham enjoyed his best days at Real Madrid, quite the opposite. He appeared 265 times for Man U over 10 years, scoring 62 goals (that's about a goal every 4.5 games, while in 4 years at Madrid, he appeared 116 times, scoring only 13 times (which is more a goal every 9.5 games). While that isn't the only indicator, he certainly doesn't seem to have had a suspicious increase in form at Madrid. AFAIK, in most clubs which have been implicated in the orgnaised use of performance-enhancing drugs it seems to have much more to do with the youth set-up, in particular the rapid bulking up of younger players.