I would not use an SLR.
If you want to do 35mm copying (for 4x5 there is the MP-4 and then, of course, there are the Linhof copying cameras) I'd just get a good repro-stand and get something like a Robot Recorder with bulk magazine--- made in 10m, 30m, 60m and 150m sizes. The 10 meter back is quite small but still allows for 250 shots in 24x36mm or 370 in 24x24mm. 10 meters is just right the Jobo and LOMO bulk/cine tanks and I think, the longest one might want to process without a roller transport machine--- and especially without a special dryer.
In a reproduction environment with the Robot, alignment and critical focus is done with a ground glass. The shutter is rotary so the camera stays completely registered in aligment. The MOTOR Recorder runs off 24v (or some as little as 12v). They are faster and provide more acurate frame registration than ANY amateur camera (including all the Leica M-x, Nikon F-x etc).
The Leica Reprovit-II is good but you need have an MDa or an M-3 (comtemporary Leica M models won't work) and maybe a Focotar-2.. bits that are still traded at comparatively high prices even if Reprovit-IIs can be had for small change.
I really like the Reprovit-II but but its not quite, I think, to the levels of Robot on a good repro stand (such as an MP-4 frame) or even one of the heavier Kaiser models.
Today inexpensive but in the days of MDa/Reprovits the Robot repro system was also very expensive. A Document system (WITHOUT Stand or Magzine but with lens, power-supply and flash) would have cost no less than $3000 USD in 1980.