Looks like that site has the plans mapped out pretty well. I say go for it. Many guys here build their own PS. Most of the are toroidal I think. Most are also much more power and perhaps a little more cost. Nothing at all wrong with building one, especially since you have some of the parts on hand. Some guys do electronic work out of love, but I do only as a necessity.
I blew out my first Xylotex with a short to ground on one motor from a rush to test. Didn't tape up an extra wire. I had cut it off flush, but it hit the case perfectly.
So, make sure you do the testing the designer suggests.
I had such a sinking feeling when this blew. I want to help you avoid that feeling at all cost.
Xylotex was great about repairing the board though.
Good luck with it and let us know how it goes.