Just some quick feedback on the Arai drum brake. My wife and I did a tour around the alps this summer and blew through four tubes, three times on steep descents and once after we had stopped. We have an Arai drum brake and were using it on these descents. All of the blow-outs occurred either coming into or out of switchbacks. Fortunately, in braking hard we were also going slow enough to make controlled stops.
We have a Co-Motion Speedster with Avid Single Digit Sevens and went through two sets of brake pads. We were towing a BOB trailer with about 40lbs of stuff and we weigh around 310lbs combined. I'm thinking now of adding disc brakes, perhaps only on the front which would require a new fork with disc mounts.