On a bike tour working on my bike in a campground, I would much rather be stringing my new inner cable (pulled from my spares) than trying to fix a hydraulic system. I might have to tape up the excess length of cable with some electrical tape because I do not carry a good cable cutter, but at least it is something that will get me rolling again. If I pass a bike shop later, I am sure I could get the cable end cut.
Why on earth should you ever want to do all of that? Are you perhaps mistaking the HSxx rim hydraulic brake system from Magura for one of their needie-bleedie, pad-chewing hub-mount hydraulic disc systems for macho men? The Magura HSxx system consists of easy-fit, easy remove grips and calipers permanently joined for life, which by all accounts is indefinite, probably permanent, by a tube that you never remove or open because the system is never bled and never requires topping up (it is totally sealed and the "oil" is totally insensitive to water). The HSxx is distinguished from all other hydraulic braking systems by fitting the calipers on the forks at the wheel rims and applying the brake blocks to the rims.
And I can't imagine anything worse than dealing with hydraulics when re-assembling my S&S coupled bike.
That's exactly my point! I've chosen this zero-maintenance, zero-risk system because you're not dealing with hydraulics: you're dealing with a sealed-for-life black box, in which is it immaterial to you what the gubbins are because you'll never have to deal with them. All you need to know is that they work better and last longer than the other rim brakes.
In the light of that, I have a hard time imagining anything easier with an S&S coupled bike than Magura S&S hydraulic rim brakes. Study the photographs in the link I published in the original post. I suppose you could use a wrench to remove the grip from the handlebar, but if it were me, I'd replace the bolts on the clamp with quick release knurled or plastic-topped screws. With one scew loosened and the other removed, remove the grip and screw the loose screw back in far enough not to be lost. You don't remove the tube from the grip. Now wrap the tube with the grip attached around the fork, leaving the calipers on the fork with the other end of the tube attached to them; the calipers fit to the inside of the fork blades which will protect them. That's it at the front.
For the rear brake, it is surely not beyond human ingenuity to arrange that the hydraulic fluid tube runs through a couple of clips (or through a reusable cable tie), so you unscrew the grip, pull it out of the clips forward of the S&S hinge, and wrap the whole around whichever part of the frame comes to hand. Again, you do not remove the tube from either the grip or the caliper end.
That should take about a minute for both brakes, if your bike is properly developed, and screwing the grips back on and clipping the rear cable into a single or perhaps two clips another minute. Max. Are your cable brakes faster to dismount and remount than that? Do they need adjustment after reassembly?
To forestall the next argument: If you can crush or abrade Magura's special HS hydraulic tube with any force your bike is reasonably likely to meet, I'll give you my spare set, and pay the postage too.
On my Nomad I am running some long arm low budget Tektro V brakes with S&S adapters, I needed these low budget ones to clear my fenders because the XT brakes did not have the arm length I needed for the wide fenders over my 57 mm tires.
You don't have to accept cheap brakes on your bike. I operate Magura's hydraulic rim brakes (HS11 -22 -33) on 32mm rims carrying 60mm Big Apple tires and SKS P65 mudguards. You don't get any wider than that on a touring bike. No problemo.
First photo is the inexpensive Tektro after I installed it on the rear, second photo shows the XT on the front (that was later replaced) and how the cable rubs on the fender. In both cases I am using a travel agent to allow me to use brake levers with the "road" brake type of cable pull.
I love your bike, George, but you don't need these make-do stratagems like the Travel Agent when you can have a more efficient, less bothersome, cleaner and probably overall cheaper brake option which has proven bombproof-reliable. Not that I'm trying to persuade you of anything -- I suspect your mind is made -- but simply to answer your points.
Thanks for helping me see that the Magura rim hydraulics are also an elegant solution to problems that arrive in the wake of S&S knuckles and to fitting efficient brakes around fat tires and mudguards.
CAVEATS
Only one man's opinion, of course, in view of a decade of incident-free service by Magura HS brakes and the fact that it is pretty hard to find a contrary opinion on the net. These brakes have been marketed for decades in a very competitive sector of the market, and Magura gives a five-guarantee. However, they don't fit most Thorn bikes because the brake mounting bosses on those Thorn bikes are a bit higher than the norm, as explained by Dave from the Thorn Workshop below. Check before you start shopping!