During the betas of Atlas Microsoft provided an update for the asp.net validators which allowed them to work in update panels, at release time these vanished much to the consternation of most people. ScottGu ("All hail ScottGu") promised a patch to ASP.NET would be forthcoming, and in the mean time Microsoft published source for sample validators. 6 months later, and still no sign of the patch on WindowsUpdate but it has appeared as a hotfix on Microsoft Connect (not that the Knowledge Base article linked to on the download page, or the extra KB article linked to in the readme inside the patch even hints the hotfix addresses validators).
The patch itself is rather confusing, there are downloads for Intel32, Intel64 and Intel64. However there's an extra download, seemingly for Intel32 only.
So for the brave souls with understanding server admins you might have a patch. Someone let me know which one works; kthxbye.