Another option is Phil at Smooth Ride in Thornton. His shop used to be two doors down from Toytec before Toytec moved to Denver. I bought a suspension from Toytec for my old FJ a few years ago and they recommended him as an installer. He has a smaller shop and is quite a bit more reasonably priced compared to Slee, RSG, and HC4x4. He does outsource his alignments.
We are really lucky to have all of these options in Denver metro. I just dropped a few grand on suspension parts for my 4R and have been debating who I want to do the install so this thread is extremely timely.
The way I see --take this with a grain of salt, I'm just some dude on the internet-- they all do 4Rs but first and foremost Slee is a Land Cruiser shop, HC4x4 is a Jeep shop, RSG is a 4R shop, Smooth Ride does general work. I'd venture to guess RSG has done more 4Rs than any of the other options and for damn sure they're the only ones to put a 4R on 40s w/ a solid axel. They are all about the same price, except for Smooth Ride.
I will probably go with RSG.