Well, if you want to go really small... this one's the case for my last several builds. I have a half dozen around the house as controllers for various things and my kid uses one as his desktop computer. Granted, it might have a few fewer features than you're after...

(Raspberry Pi).

 

You might want to take a look at the SG01-F and the
SG04-F by Silverstone. Both good cases.

 

You're not wrong. They can do a lot of things and are a hobbyist's dream, but are underpowered for 3D gaming and such. (Then again, they're all of $35, so one can't go into it with too high of expectations.) I got the kid a USB HDD to go with his, which I'd recommend if you're going to use it as a desktop stand-in. He does most of his schoolwork on it, browses the web, etc. And it's pretty well integrated with Scratch and Python for an intro into programming.

I have one with a wireless USB that lets me program the coffee and espresso machines from my iPhone (yeah, cheesy). Another runs our entertainment system. I rigged up a third for the local fencing club as a DIY timer/scoreboard.

 

Haswell's real strength is in the mobile environment. It's simply too good with power consumption and efficiency, which is less of a concern on a desktop. If I were building one now, I'd go with a last gen i5-2550 or so. Not only will it be cheaper because it's "old" tech, but it'll do what you need.

 

Yes, about 30% or so, but if you want CPU that has a good integrated GPU then AMD would be your best bet. For example, the GPU in the A10-5800k has about 25% more performance than the one in the new i7-4770k.

 

Two months later... What did you get?

On the odd chance you didn't get anything, I built a gaming PC with the Silverstone SG05(450W PSU) that has a 4670K and GTX 770. So.. yeah that nice small case is good.