We’ve seen people produce some fairly impressive effects using our LR2/Mogrify plugin for Lightroom 2 and a little imagination.
The latest incarnation of this plugin should allow you even more freedom to experiment with your creativity. Until now you’ve only been able to add borders to the outside of your images, but with version 3.00 you can now add borders to the inside too. By playing with the opacity of each border you can produce some great effects.
Here are a couple of examples. The text annoations have been added with the plugin too, of course.