Look this over:
http://www.micromatic.com/draft-keg-...s-cid-616.html
You'll see that you can pretty much mix and match the regulators if you want. There should be no cutting, welding or indepth fabrication needed to do what you are wanting to do.
And FWIW, there is not a huge difference in price in the economy, classic or premium regulators. I'd go for the premium regulators.