Not to be a jerk, but that sounds like a really good way to kill yourself. Playing with 10+ amps is not a good idea.
Yes PSUs are transformers, but they're also filters and some other stuff.
No offense taken! I don't know much about electricity yet... but it sounds like a pretty simply job.
It SOUNDS simple yes but that's merly because you don't know anything about it... Don't throw yourself at it because:
First of all it will take at least a month to just read up all the theory behind (and that's assuming you're damn smart)
Secondly there's a huge bunch of safety hazards
Thirdly it's a huge investment because quality capacitors aren't cheap and you'll need that for 24/7 operation
Last but not least: It's MUCH more difficult to build a big powersupply rather than a lot of small ones...
Moral of the story? Don't waste your time on it