I currently run 2x 2408WFP and 1 2407WFP in Eyefinity. Works great. The 2407 looks nearly identical (the only different is the menu buttons). The 2408's were $500 apiece and the 2407 was 225 used. I'd reccomend going with 1 2408 for the middle and the 2 2407's for the sides.
The 2407 is on the left. Can you see the difference?
They're powered by a HD5850. Games I've tried include:
GRID
Supreme Commander: Forged Alliance
Mirror's Edge
Civilization 4
TF2, L4D2, HL2, etc (all source games)
NFS:S
Stalker: CoP
The Witcher
All of these game had playable framerates at max settings with v-sync on. GRID is simply amazing at 5760x1200 maxed out.