Alex, diodes only 'seem' to solve the problem, what you're not taking into account is all the feed back effects that are occurring. You will get voltage/current oscillations all over the place with multiple parallel/serial power supplies using diodes on the output. One power supply has enough ripple as it is, two or more is going to add to the ripple, and WORSE the ripple will feed back into the other supplys effecting their otherwise closed loops. And I don't mean the current will enter the other power supply, but the two loads (especially if they're out of phase and they will be) will be constantly chanign load conditions. If the peak of one supplys voltage out occurs at teh same time as the valley of another voltage out occurs the diode will effectivly block ALL current from one supply and overload the other. The feedback and oscilation will get worse the more power supplies you add in parallel. You would need to keep each power supply PERFECTLY in phase with every other, and there's no practical way to do that.