Well I doubt that would work, very few MOSFETs (in lightweight packages) can take 100A without melting. You'd have to add more MOSFETs in parallel, use MOSFET driver chips to switch them, and replace high-side p-channel FETs with n-channel (lower Rds(on) - the driver chips do the rest). FAN7388 3-phase driver is a good choice that I've played with recently (handles 600V should you need it!!)
At higher voltages and currents protection circuitry gets more important - you must monitor over current, that's a given. Unless you use switched commutation you'll probably need 100A schottky diodes in parallel with the MOSFETs to reduce the free-wheel diode losses perhaps?