My wife and I are currently in the middle of a multi-year world cycle tour: http://www.goingslowly.com/

Our Velocity rims failed in Switzerland a few months ago:
http://journal.goingslowly.com/2009/...city-rims.html
http://journal.goingslowly.com/2009/...rs-arrive.html

Velocity was great and replaced our entire wheelsets for free.

We're now experiencing the same failure on my wife's rear rim.

Velocity is willing to send us ANOTHER wheelset but this time around we need to switch to disc brakes. We need cable operated disc brakes that will mount to a pair of Surly LHTs with Tubus Tara and Tubus Cargo racks. My wife has trekking bars, I have drops. I'm not sure if our existing brake levers will work?

Our complete gearlist down to the brakepads is here:
http://www.goingslowly.com/gear/

Any advice you guys can give would be greatly appreciated. I've never dealt with disc brakes but I need to figure out what we need and soon. Hopefully Velocity will be willing to send us the brakes with the wheels if we send some money because we're on a desert island off the coast of Tunisia right now.

Thanks!