Alternate solution: What about modifying a tow dolly to add the surge brakes? That way, you'd drive the front wheels of any vehicle up onto it, strap it down, and drive away. The trailer itself would handle the braking (2 wheels, not 4, but ...), and you'd have an option to haul any vehicle, not just one specially prepared.

 

I've been motorhoming since the '80s and tried a tow dolly for awhile. The thing weighed 500lbs all by itself and was hard to stow after I was parked at a campground so after a couple of years, I gave up on it but thanks for your suggestion. I tried to driver around a motel one time - it was a dead end. It took me about 45 minutes to take the car off the dolly, take the dolly off the motorhome, turn the motorhome around and put everything back. It was soon after that I started towing 4 down.
There's a couple tow dollies on my local Craig's List but they want as much for them as they do for a braking system.

 

See, that just shows that you've been down that road before! I haven't, and so my idea didn't pan out.

Next up: Does the cable for the brakes have to be installed in a certain location, such as in line with the pedal, or can it come into the cabin at a different location?

 

It has to go through the firewall directly behind the brake pedal. It's in a sheath so it can do a little twisting and turning as it goes through the engine compartment but no really sharp turns. Then it's fasten to the tow bar bracket at the front grill.