I use the razer exactmat. Works fabulous. 10.4" x 13" x 0.1"
Probably a bit spendy for most peoples tastes, but i don't regret the money a bit.
It's funny how when i realized how little I actually move the mouse at 4k DPI. move it like an inch or two in every direction. The pad size is quite huge lol.
C2D E8400 | Diamond 4870 X2 | Biostar Tpower I45 | 4GB G.Skill PK
Corsair 750TX | Xigmatek HDT-S1283 | CM Haf 932
2x Seagate 1TB 7200.11 | Asus Xonar D2X | LT Z-5500's
Razer Lycosa | Razer Lachesis | LG L245WP-BN 24" MVA LCD