here is a simulation @ 50khz & 17uh effective, 144v in, 510v/70a out. Average switch current is 180A (240 rms), peak at 310A. Havent looked into switches much yet., any thoughts? This approach would be like rewinding a small motor though. About $100 worth of 26 gauge magnet wire, though I'm using a somewhat conservative 3a/mm^2
Edit, I've got a 6MBI100L-060 that can do %72DC @20k, so I should look at 3x interleaved I recon and see what happens to price/wire at 1/3 the current.
edit2: ouch on highflux
http://direct.mhw-intl.com/ch1016060e.html