I need a Mac for building to iOS (using Unity3D) and I have one, but it's running 10.4 and apparently that isn't good enough, 10.8 is required. So I have two questions: 1. Is there any place where I can go with a timeline of Macs and can look up which can do what? Or, failing that, could someone tell me what the oldest model(s) are which could serve my purpose? I have a preference for a laptop, but I could deal with a desktop if the difference in price was large. 2. Where is the best place to buy one of these? There's always Ebay of course, but I was thinking of maybe something like the thinkpads.com forums, which have a great marketplace. Is there anything similar for Macs?