The only reason I've recently been looking into mini-ITX is because I frequently travel cross country via plane. I wanted to make something small enough to fit in a large, carry-on-able backpack, but still be able to pack a GTX680 in there. I usually just take my Asus G71 laptop, but the Duo Core CPU and GTX260M GPU are really starting to show their age. I don't want to keep buying new laptops. I'd rather have a small box I can just swap components out of every three to five years.
The Silverstone SG05 seems to be as small as I can get right now without ordering from a company to custom build something themselves (Falcon NW's Fragbox).
One improvement I would definitely like to see on the SG05 is removable filtered perforations. There are perforated sides, but no filters.
I also want to use an H50/H60 CPU cooler in the case, but the only place to mount it is on the front intake, which gets rid of an unobstructed intake as the GTX680 is sucking from the side, the PSU from the inside (mounted upright) or the top outside (mounted upside down), and the H50/H60 either exhausting or intaking in a push/pull setup. A perforated top with a removable filter would be nice to mount the cooler to, moving the HDD/ODD slot on a 90 degree turn off to the side or something out of the way for people who would rather use a heatsink and fan to cool their CPU but also allowing people who want to use a 120mm radiator to have the option to install a slimline ODD, multicard reader, etc.
Next, I'd like to see a custom 500w modular PSU with a GOOD fan in it and a removable filter and at least a 80+ Gold efficiency rating. Since the case is emphasized on being as small as possible but allowing the highest tier of single, dual slot cards, I think anything above 500w would be unnecessary.
Also, maybe not standard with the case, but it would be cool to be able to buy a shortened and SLEEVED PSU cable bundle thing...
And, make it pretty, please! The flatter, the better. Backpackable! I have faith!