I definately think you want to go with 26" wheels.

The Bruce Gordon BLT costs $2119 complete including racks.
The REI Novara Safari costs $849 complete with rear rack.

Advantages of the Bruce Gordon.
*Handmade frame by someone whose been at it a long time.
*Steel frame.
Widely believed to have a better ride than aluminum.
*Hand built wheels.
Read what Rodriguez Bicycles says about handbuilt wheels. http://www.rodcycle.com/
Click on "Touring Bikes" and then on "Rodriguez Adventure" and then on "handbuilt wheels with a 3-year warranty".
*Welded racks made of chromoly.
Stronger than aluminum, no fasteners to come loose.

Disadvantages of the Bruce Gordon.
*It costs $1270 more.
*No disk brakes.

Advantages of the Safari.
*It cost $1270 less.
*Has disk brakes.

Disadvantages of the Safari.
*Frame is of unknown origin, unknown quality.
I've been to REI and seen this bike. The frame looks beefy. I've ridden anonymous aluminum frames like these for years and have never had problems.
*Aluminum frame.
*Wheels are almost certainly not hand built.
This would be more of a concern to me than the frame. But, the Safaris wheels look good. They have 36 spokes which is unusual for a 26" wheel. The Bruce Gordon has 36 spoke wheels too.
*Aluminum rack with many fasteners.
*Has 48/36/26 chainrings instead of the 44/32/22 chainrings of the Bruce Gordon.
Lower is better for fully loaded touring.

I'd go with the Bruce Gordon.
The Safari would probably be just fine but your planned tour is of an extreme nature. I'd want to have no doubts about my bike.