You probably won't find one until all the uproar over the new retina models subsides. The non retina models appear to be an update on the 2011 versions. If history is any indication there should be a modest update in benchmarks as well a few physical changes. The USB 3 should be a great enhancement. The updated graphics card is a plus as well as the upgraded memory.
Not sure what you use your computer for but you might also consider a late 2011 model. They are great machines also and you may be able to get a super deal on one.