After combing though a bunch of discussions on this subject, I thought I'd share my conversion and things I've learned along the way. The way I did required a lot of custom fab work so it probably won't be for most people but maybe someone will find some use in it. If anyone has any questions I'll do my best to answer them!
The steering valve is a Danfoss OSPM 100 PB I got from ebay, this one is from a John Deere 7700A (JD# TCA17008). The PB models have a power beyond port which I just tee'd into the return line right below the unit. If you find an ON unit instead of a PB you can avoid having to do that, they are identical minus the 5th port. The 100 is the displacement and has worked out to a good match. An 80 would take more turns, a 50 would be too small for the ram I used. The body diameter is small enough that it fits in dash without moving the levers when moved forward about 3/8" from the original location. It's mounted from the bottom of the dash with a 1" spacer which leaves it a little higher than the stock wheel which I think makes a better location overall.
The priority valve is a Buyers Products HFD075, again, cheap from ebay. I put it in between the travel valve and the loader valve so it isn't robbing flow from the travel motor which needs all the help it can get. It's physically quite large but it's pretty much the smallest I could find without spending a fortune. The original line was just cut and flared and left in is normal place. Bending up the tube to go from the priority valve to the loader valve was a real pain because it barely fits but the rest of the lines were pretty straight forward.
The ram I had left over from an old commercial tire change machine I dismantled. It's 2-1/8" bore and 1" rod. I shortened it to about 3.5" stroke and added spherical bearings to both ends as well as custom ports. I've seen lots of talk about using 648 parts but one of the things I haven't seen mentioned was that the B48M motor mounts are way higher than the CCKA. This means that there is very little room for the ram. To get it to fit I cut had to cut a part of the frame out at the lower, back end of the cylinder. Even still at various points in the steering/axle articulation it just barely rubs on the front motor mount bolt, the frame rail at the front motor mount, and the steering main arm. This is also the reason for the hydraulic ports. I probably could have just pulled through hoses but they would have rubbed on a ton of stuff and I didn't want that.
Anyways, some pictures!
The original cylinder
Bored out for a spherical bearing
Threading the cylinder rod
Welded up with the new ports
My JIC flare tool (punch not pictured)
Cad model of the short tube. It helped a little but I still made it wrong the first time haha
Home made tube bender
The original loader valve feed line
Priority valve installed with the short tube. The tube at the rear is pressure to the steering valve
Steering valve installed in the dash
Ram installed in the frame
And a video of it working! Probably the best upgrade I've made, it makes it so much more pleasant to run