I just pushed an update to the Custom Controls for TFS (WITCustomControls) project today. The project has been idle for a while but I decided to do a some work to enable the controls to work with TFS 2012. Soon after that pseranne contributed with a TFS 2012 Web control for the MultiSelectList control, which is the reason for the latest release.
These are the two recent changes:
22.214.171.124 release added support for TFS 2012 Windows Controls.
126.96.36.199 release added the MultiSelectList as a Web Control for TFS 2012 making the control available seamlessly in all TFS clients:
Microsoft Test Manager
Read more and download the controls from http://witcustomcontrols.codeplex.com/