Yea, it doesn't work that way.
Surface mini and Surface 1 and Surface 2 are all fanless. While the mini is not out, it's doubtful that it will be.
Sadly, Microsoft can't take a magic wand and go, "Fanless!" and poof, we have a Surface Pro fanless.
To make it fanless, it would need a MUCH MUCH MUCH larger heatsink and more air vents, making the device MUCH more thicker, and MUCH more heavy, as copper is heavy. Not to mention, much more expensive as well.
OR, not do that, and about a couple of minutes of usage, the system will throttle down to the slowest speed supported, due to the overheating protection system kicking-in. And then you'll complain that the performance you are getting is slower than the slowest Atom you could buy, and complain on how that is not what you paid for.
The only solution, is that Intel releases a processor, not of 15W (what it is now) not of ~10W (next gen... maybe.. rumor), but rather ~5-3W, like ARM based CPUs in tablets, at the SAME time (as we have Atom CPUs), provide serious performance. And that is also, not a magic wand trick. No Ultra-Low voltage super slow models either, and certainly not Atom, as both are crazy slow processors.
But if you don't care about performance, then why don't you get the Dell Venue 11 Pro? The Atom base model is fanless already.