I have been planning on doing this for a couple of years, and just got around to it this spring. My trailer is a triple axle 15K lbs gross trailer with disk brakes on each axle. It came new with a surge coupler, which worked fine, but was not ideal for several things, such as long downhills and the 'thunk' you get pulling away from a light.
I ended up going with Titan for both the actuator and their 20K lbs bolt on coupler. I went with a Dexter breakaway battery, since they have a single battery whereas the Tital system uses two smaller batteries. I ordered all of these parts from Etrailer.com. I also got a mounting pedestal from pacifictrailers.com that raises it up off the trailer beams to protect it from getting in the salt water (people say this is what wrecks these systems when they get accidentially submerged). The one 'gotcha' was that the pedestal was designed for the Titan two batteries instead of the single Dexter battery, so I had to cut off this adapter and reweld it to fit the Dexter system.
So far so good, the system seems to be working fine, although I am not planning on hauling the trailer for a couple of weeks. One noce thing about this system is that it makes bleeding brakes easy. I just used a set of vise grips to hold the manual control on my controller slightly on, and there was pressure at all of the brake bleeders.
I think the total charges came in at around $800, and it took me 4 hours or so to complete. I was a bit unsure where to put the system; it seems like it can go anywhere that is out of the way. Here are a couple of shots of the system.
I know, the wiring still needs some cleanup. I got the Titan II actuator, which comes with cables to just plug your trailer plug into this system, but I cut off my trailer plug and the end they plug it into and hard wired this, hopefully for better reliability.
Anyone need a slightly used (2 years old) surge coupler? I will have to get arould to put this on CL at some point this summer. Seems like someone should be able to put it to use.