I'm reluctant to share this actually...
...but a
blade server power supply could potentially be used for this.
They show up on eBay for well under $100 quite regularly, and push out over 175A at 12V.
David Edwards, a mentor for 1310, and I have thrown around the idea of modifying one of these to power a functional FRC robot.
But truthfully, I have never pursued it, because I simply don't trust myself enough to modify something that puts out that much power.
If you have an experienced power electronics engineer at your disposal, then maybe you could safely give this a shot.
If not, please do not try this at home!