I suggest Asus Rampage III Extreme, it gives you the spacing you want (Using the 16x, 8x, 8x config), includes USB 3 and SATA 3. It does come with a bit of a price tag though.
Ummm but if I use 16x,8x config ... I'll loose some "power" no ?
On ud3r I think I could use 16x,8x also (and solve my heat prob), I pay for 2 "big" video card I 'didn't loose anything