The components from the UI for Silverlight suite can be used to build Silverlight custom controls that can be used within LightSwitch screens. We have a few blog posts describing this approach:
- How to Use Telerik UI for SIlverlight in LightSwitch Beta 2 (http://blogs.telerik.com/vladimirenchev/posts/11-04-07/how-to-telerik-silverlight-components-in-microsoft-lightswitch-beta-2.aspx)
- Consuming LightSwitch OData services withVS2012 and Telerik RadDataServiceDataSource(http://blogs.telerik.com/vladimirenchev/posts/12-09-10/consuming-lightswitch-odata-services-with-microsoft-visual-studio-2012-and-telerik-raddataservicedatasource.aspx)
 - Custom paging with RadGridView and RadDataPager for Silverlight and VS2012 LightSwitch(http://blogs.telerik.com/vladimirenchev/posts/12-08-29/custom-paging-with-telerik-radgridview-and-raddatapager-for-silverlight-and-microsoft-visual-studio-2012-lightswitch.aspx)