Attached Link: http://www.pinnaclesys.com/ProductPage.asp?Product_ID=110&Langue_ID=7

Pinnacle's Commotion Pro 4.1 has an effect called Super Rack Focus that can be driven by a depth map (such as the Distance G-Buffer in Carrara). The only catch I've found so far is that I have to pre-process the depth map (distance g-buffer) in Photoshop before going into Commotion (otherwise Commotion sees the depth map as an alpha channel). This seems like a relatively painless way to accomplish depth-of-field effects and you can also do some fun things by changing the focal point over time (I guess in film-land they call this rack focus). I've attached an example of how this looks in Commotion (and thanks to Litst for his always helpful Real World Carrara Metals shaders).

Commotion Pro (the non-pro version is missing a lot of the good stuff) has some other effects (such as Light Wrap, Matte Feather and Composite Color Matcher) that are great for compositing 3D objects more realistically into scenes (just render an object in Carrara along with a Mask G-Buffer [alpha channel] and then do the compositing in Commotion).

Seems like After Effects and Combustion get all the press but so far I've been very impressed by Commotion. If you know After Effects you'll find Commotion very easy to use since the interfaces are remarkably similar. Commotion Pro isn't cheap but if you're already considering the upgrade from After Effects Standard to After Effects Production Bundle you might want to check it out.