I don't think the pump would be as much a problem with two AMD procs as much as heat dispersion would be. I have never used the kit so I couldn't tell you positively, but looking over their kits I'm not sure the radiator or reservoir are up to par for two CPUs.

I definitely think watercooling is a solution for you, but why not try to piece your own kit together? There are a lot of water cooled members on this site and we'd be glad to help. I put my kit together myself, but may be a little bigger than what you would like.