Nice example! This is indeed one of the capabilities now available with LR2.x (Release Candidate 2.1 available at this writing).

Having a library of potential frames also aids in 'proofing' for how the final product may appear! Color and proportion can be a costly set of options! I've used a couple of different solutions to look at style of framing and it looks like with a little bit of PS work I can build all that into the LR workflow as well!!

Thanks again for adding your experiences to this topic.