You didn't mention just how many amps at what voltage you actually need. I built about a year ago a design from Elektor that works in a similar way to a Switched Mode Power Supply, but with most of the dangers to the user removed.....also, with the chips noted, you can have 10 amps at up to 40 volts. With other chips, you can have even higher voltages......if you want full details, I can post them here for you, just let me know......it was easy to build, easy to set up and is around 85% efficient, almost as efficient as a top SM Power Supply....and with the plus that I know EXACTLY how it works and I can easily repair it if ever needed.....all the clever stuff is in two identical chips.....
Regards
Andy