Control Builders & ASP.NET Generic Control Classes

Since the release of .NET 2.0 and ASP.NET 2.0 I was very disappointed that new language power of C# 2.0 is not available for ASP.NET developers. It was stressed at the time of release by multiple people (see here, here and here). While generic classes are not supported in ASP.NET markup in general, it seemed to me that it is still possible to benefit from generic in ASP.NET in many cases.