I currently have a 2yr old 15" MBP and have decided I really want a smaller 13". However, I don't yet want to buy a new one as I'd rather wait for the redesigned MBP I assume will be coming later in the year/early 2012. So I want to sell my 15" and get a not-too-old 13". Two questions: 1. Where is a good place to buy that is not eBay? 2. How can I tell which gen a 2nd hand MBP is? Ideally I want the generation that's just been replaced.