Does it have to be a mini-PC like that? If you can put together a PC (or know someone who'll do it for free/cheap) you can get a significantly better midi-tower PC for less money.
Edit: And if you're going for the high-end version of the Meerkat then you have over $400 to blow for the service of putting it together and you still end up with a more powerful self-built machine. Which is also more extensible in case your son wants to put in a dedicated entry-level graphics card later on. Midi-Tower PC, CPU comparison, GPU comparison