Cord, I was just looking into possibly upgrading my drums to disc. I was picking up some grease at Tom's Trailers ( you just gotta love the guy if you've ever had the displeasure of meeting him) and they quoted me $250 per axle for stainless steel discs. It might be worth looking into if you only have brakes on one axle. I've got them on all three. I don't know if you'ld have to change else, but I think it's just a simple swap and hook up the brake line. Good luck on your project! Steve

Did the conversion two years ago myself. Had single axle drums...converted to single axle disks. It didn't stop as well and the pads wore like hell. Last season I added disks to the second axle...that sucker STOPS now;) .
You must also remove a check valve from master cylinder. Instructions show you simply drive an awl through it. I did and it worked.
To do it right you should also add flex hose at the end of the metal lines going to the caliper as it moves unlike the stationary backer plate on drums.

509-I know exactly what you are talking about. If you want to shop for price take a glance at Norther tools. They are in Menomonee Falls, just north of Tom's. They often have the same item for significantly less than Tom's. Now if you need a oddball trailer part like a magnet for a 12" drum brake, Tom will have it on the shelf!

Trailer Parts
http://www.expediter.com/index.html

if you go with disc brakes you should get a reverse lockout solenoid it makes backing up easier, discs grab in both directions unlike drums

Go buy electric drum backing plates. They last longer than hydralics in fresh water, work better on the road, and will never form rust in the cylinders.

It costs the same as a hydraulic backing plate and you can re-use the drums. Just add some wires to the tongue and have the master cylinder welded in place.

You will need a controller for your truck but they are cheap - less than $100.

It works great in reverse down the ramp if you have a big boat!

Steve