Basically just a small form PC. Pretty much every component that will be messed with is just an off-the-shelf part. Not really any surprises here, but it's nice that it's all confirmed.
The other components are easy of course.
I'd be happy to be proven wrong, because I'm definitely in the market for something like this. More than 50% of my gaming time happens when I take time off - which usually means I'm visiting family for a few weeks, and taking anything bigger than this on a plane or train is not realistic. I was hoping Thunderbolt might solve the problem with external GPUs, but right now that seems more trouble than it's worth.
I tried that, many years ago. I'll be the first to admit I'm not especially good at working metal, so it was somewhat crude. Keeping everything safely in place inside, and ensuring sufficient thermal flow ended up too much of a challenge for me. The thing only ran stably when I left it open, and eventually a heatsink came loose during travel. Might be easier with today's more efficient/better designed components, and with a bit of hindsight. Still, very much a major project.
I believe there are also ITX or micro ATX cases that can accommodate a 400+ watt PSU for powering a GPU in that range.
Every 6-12 months I review the market on these. You can indeed get ITX cases which will take a graphics card. Generally, the form factor is the "cube" kind (well, square-ish front face), around 20x22x35cm. (~15 litres) I find this much harder to transport safely (e.g. by packing clothes around it in a suitcase) than the flat, "VCR-shaped" arrangement, with the graphics card on a 90° riser. The ones on the market also tend to waste space on optical drives, multiple hard drive bays, etc. and often have external PSUs (not necessarily a bad thing, but often they don't make the case any smaller).
The Steam Machine prototypes are apparently only around 7.5x31x31cm. That's less than 8 litres, including the PSU.
Last time I looked into this was in Spring, so maybe things have improved since then. Specific suggestions welcome.
It seems like they would have something that Bitcoin doesn't, a lively economy and marketplace to add stability.
You'd be better off introducing a Call of Duty Coin... Call them Dogtags or something.
You can check Steam user counts here (http://store.steampowered.com/stats/).
Not sure how console user bases stack up, but that's a pretty wide base.
Wow had 12M at its peak.
And there is huge overlap. LoL gamers and WoW are subset of steam users.
http://steamcommunity.com/market/
Most hats aren't saleable on the market, but you can trade the hats for keys, which you can sell for about $2.25 a pop.