Don't think that PC PSU is any good for this purpose. Not only they are more than two times bigger but also very thick compared to this MW one. Therefore much thicker enclosure is needed. Some of them also have a problem to work normally when other power rails stay without any load. As of modular PSUs, there will be a lot of permanent wires in addition to detachable ones anyway. Just don't see any reason to use ATX, no price, no size, no reliability advantage. That would change drastically if you would need something in 1000+W realm.