Brandon at Sky's Extreme in Clearfield UT SXOR does custom stuff for all types of applications including Government tactical buggies.
OTB Off the Back fab in Ogden, UT has a nice plasma table and will burn parts super cheap if you email DXF files ahead. They do fabbing as well, small shop, one man show.
Lakes Fabrication, Owner Dekon. Layton, UT Him and his son have a small shop and do great fab work. Mostly hot rod stuff and rhino cages for manufacturers by the quantity.
Depends, I could list many people that would get the job done right and in a timely manner. I avoid people that take their sweet A$$ time and quote you wrong.
I even do fab work for people, but like to work on my own things. Funny thing is that I have nicer tooling than alot of shops in UT.
If you want dimple die holes everywhere and clean plasma or laser parts, TIG, custom DXF drawn for your application, well hard to say. I know Ben Hanks did some good work and had the correct tooling, actually they were the only oneS I knew that had their crap together in the quality department for Northern UT.
Sexton Offroad in Kamas has a nice shop.
Sure others will chime in and update you with many others out there. One thing to look for in a shop is that it competes or is in a race circuit, having history in the offroad department...