Recently I found out about xVal.WebForms project at CodePlex.com. Its a good implementation of XVal for ASP.Net WebForms made by John Rummell.
I missed Validation Summary support so I upgraded John’s code so it could work with XVal 1.0.
I submitted two patches modifying ModelValidator.cs and xVal.jquery.validate.js.
These changes are now part of the Trunk repository as you can see here:
http://xvalwebforms.codeplex.com/SourceControl/PatchList.aspx