If you're going to go with 1156 socket, why not just go with a 760? Since you are planning on cooling the cpu anways, you could definitely oc the 760. 460 is a great pairing w/ this setup (imo), since it has pretty low heat output and low power draw. Have heard some iffy things about the EE EVGA setup, as some prefer the open face versions.
Don't listen to the mini-ITX haters. ITX makes a perfectly viable gaming system, providing you choose the right case. Sure, they're small and there's not a lot of room on the inside, but that doesn't meant they wont work, especially if space saving size and portability are important.
The Gigabyte motherboard your looking at will handle any of the LGA1156 Lynnfield and Clarkdale processors including the i7-860S
EVGA recommends a minimum 450 watt power supply for that card so your ok there. There wont be a lot of other hardware drawing power on a mini-ITX system. It's a good choice for a mini-ITX build. The other would be a Radeon 5850/70.
The case is also a popular choice. Many mini-ITX builds are using the Sugo's. You might want to check out the new mini-ITX offerings from Lian Li. They have the PC-Q08 mini-ITX case that is quite small and will also fit a standard PSU and has 2 expansions slots for your video card.
Try the cooler from that article. Another popular choice is the Corsair H50. The bracket needs very simple modding to fit the GA-H55N, but its popular in the PC-Q08 ITX builds. Don't know if the Sugo will have room for it.
There some more great mini-ITX gaming information at ITXGamer.