I don't know where in the world you are, but in North America, I am a fan of Dell Xeon-based systems. I am running a T7500 w/ 192GB, but if I had 10K I would look for a
T7600 or
T7610 at one of the off-lease sites or Dell outlet. They're dual-CPU and the inventory changes pretty frequently on the outlet site. The 7610s can do up to 512GB of 1866MHz, but they only take ECC so it's $$$.
I've always liked the cases. They're roomy and easy to work on. And it's got a 1300W Power supply which is nice...
Last I looked here there was a whole lot of discussion on Xeon vs i7, and i7 was better for single models with Xeon better for multiple reconstructions at the same time, but I think for that much RAM you'll need a multi-cpu system.