> There's an uncited mention on Wikipedia

Interesting. This line was added to the English article about a year ago as a translated import from the German article (which has it since October 2006), where it reads (proper English translation from me):

"Over-clocked variants at 100/133 MHz are said to exist (partly in connection with water cooling)"

Notice the (not so) subtle difference from the line in the English article? :-)
Request for backing was then rightfully added to the English article in November 2010. The German article while missing a backup for this line as well never had such request, though.

> How far are you willing to go to find out? E-mailing the author of
> the page for more information?

Sure, I could ask the Wikipedian who changed "said to exist" to "exist" in his attempt to import and translate the line from one article to the other for his reasons to do this. Or I could ask the other Wikipedian who originally put the (more qualified) line in the German article for his source. However, I won't do neither ;-)