Velocity Dyad are 700c rims not 26 in(559). Velocity has Aeroheat in 26 which are good rims.I would go with a rigid fork and use fat tyres for some suspension. The on-one seatpost is good quality and should be fine.

Cranks , Go for integrated set with external BB, the new LX is more ahybrid style. get an older model M582or M580 get 22,32,44 size because when your struggling up a steep mountain you cannot get low enough gears

Hubs look at www.chainreactioncycles.com they have Shimano Disc Hub Front M475 in 36 hole quite cheap.

Look at the following for some MTB tourers http://www.bikeforums.net/showthread.php?t=334033