I'm trying to fit a secondary braking system to my steel tandem which currently has only vintage Phil Wood discs (allegedly prone to failure, thus I want a backup). The front is drilled for a brake, but the rear brake bridge is not drilled and isn't robust enough to drill.

I've seen these brakes online, but never in real life. http://www.velodromeshop.net/index.p...roduct&id=1253
It appears to be a nutted brake caliper and two pieces of aluminum that clamp on the seatstays.

Anybody used this or something similar on frames not drilled for a rear brake?

Are there any other options? Eventually I will have cantilever or modern disc mounts brazed on, but that's not in the cards right now.