Mike Morton and the Visual Studio team that created the SharePoint tools have released a VS 2010 SP Power Tools pack. The Power Tools pack includes a Visual Web Part that can be deployed as part of a Sandbox Solution and an extension to display build errors when a developer inadventantly uses types or members in a sandbox solution that are not allowed.
For those who have not yet used a Visual Web Part it is a Web Part that encapsulates a user control which allows for a very nice design experience but up until now it was not allowed in a Sandbox solution. The ability to create a Visual Web Part and place it in the sandbox will make it easier to deploy Web Parts. Hats of to Mike and the VS team!
Download the VS 2010 SharePoint Power Tools at:
http://visualstudiogallery.msdn.microsoft.com/en-us/8e602a8c-6714-4549-9e95-f3700344b0d9