Why? Because you, personally, want to buy a $25 (+ Apple premium) circuit board that runs OS X? (And surely with that hardware you'd be more likely to get iOS?) What would you do with it that you can't do with a Raspberry Pi + Raspbian, or a pogoplug, or etc?<p>Or do you think such a product would sell like hot cakes? Why? What sorts of people would buy this? What would they use it for? Why aren't they using a Raspberry Pi etc? Or, how would this be better than a Raspberry Pi?<p>Perhaps instead you want Apple to build something like the Raspberry Pi in the same way that people used to want Apple to build a netbook? Apple built the ipad instead: a response to a need that netbooks were imperfectly satisfying, and addressing it head on. What need is the Raspberry Pi imperfectly satisfying? What would a product that addressed that need head on look like?
I actually wish Apple would have emulators for their old hardware: The original Mac line, the Apple II, the Lisa and yes I would kill to run NeXTstep. A few years ago I could see the argument that this might encourage people to upgrade, but frankly Apple should know by now that desktop personal computers aren't the wave of the future — so why not have some fun with the past? Also it would be good branding...