A look at how the latest version CarrySpeed VFinder attaches to a Canon 60D with that swivel out screen. Right off the bat the metal frames might not line up perfectly, but they are easy to bend into position. If you want something super secure, I say permanently glue the sucker to the metal QR frame.
The 3:2 viewfinder fits perfectly on this Canon 60D and it is slightly slotted to fit the Canon T3i as well. The CarrySpeed viewfinders come with a Neoprene pouch, a Lanyard, Metal Frame, and the VFinder loupe. Not a bad deal for an important tool to help you set focus and dial in proper exposure (especially on those bright days). You might want to add some Anti Fog solution too.
Canon 60D / Canon T3i LCD ViewFinder Quick Frame
[Update] Also available via Amazon below
CarrySpeed LCD ViewFinder