I`m sure you could have one made. They may not be an off the shelf item. We have a 7.5 kva at 12 volts that heats a knive. We actually had a transformer co. build one to get a heavier secondary because it kept burning the leads off. I would figure a 20 kva at 24 volts wouldn`t be a problem.
I think we used Texas Transf Co. to build ours.
Well, I couldn't imagine needing this many amps at 24V either until I had a request for a test stand with that capability.
Eric:
Thanks for the reminder about Global Spec. Sometimes google is just too crowded or if momentary brain block keeps you from finding the right search phrase you get all sorts of weird results.
I know that they are out there, I work at and Electro-Plating facility (ahhhh look at the shinny chrome) the biggest rectifiers that we have are 0-15 VDC 10K Amps with less than 1% ripple. Go to www.zinex.com they will custom build any size rectifier that you might need. Not sure how much they would charge but they have great quality