You apparently have been living under a rock for the past couple years if you think passive cooling isnt ever a good idea. While I think an i7 probably shouldn't be passively cooled, at least with this system being almost entirely a heatsink, you could just put a fan in front of it and problem solved. I get your point about metal saturating heat, but heat needs to escape into something at some point. Otherwise things like tablets would overheat all the time.
But 1- Passive cooling is never a good idea, no matter if you think it looks good. Get some flowing air or liquid or something because there's a point where metal saturates with heat.