Please provide more details, I would love to hear this...
But I think even 10k is more than enough.
Just get a dual xeon or the new extreme if single threaded performance is important to you. Couple 840 pros, 128 gb ramquadros for work, gtx 680 for a mix of CUDAs/gaming performance.
Fill the rest of budget with gold heatsink/radiator if watercooling (I hear it conducts better than them copper stuff-pfff, copper...)
You honestly won't need 50k, it's veen hard to get to that budget, but prove me wrong.