Here you'll see that the H50 keeps a 150 W source to 20.7 degrees C above ambient and the C12P keeps it 21.2 degrees C above ambient, so not that much difference really.
A cut and paste error I think, both the ECO C80 A.L.C. and ECO C92 A.L.C. have the same text in the shop, apart from the sizes. If you look at the specification tab and the downloadable pdf specification sheet, its 92mm.
I'm after a SFF gaming setup and if I go for matx, I'm thinking of the NZXT Vulcan or the In Win Dragon Slayer (getting a bit too big). However, the Vulcan isn't proving to be very friendly for X58 heatsinks :(
For a cube style case I'm thinking of Da Box from Lan Gear.
Been lurking in this forum for a few days now, and I'm also after SFF gaming setup. I see a lot of the H55 boards have heatsink issues due to the placement of the CPU on the board. This one seems to have a better placement, no reviews for it yet that I can find.