I've built up 5 bikes from the frame up, and I still stick to the recommendation to buy a stock bike for you first touring bike. Build up a bike if what you want is not availabe, and you really know what you want. I've had a lot of bikes, all the tools, know components, and have lot of touring experience. I knew what I wanted.

Also, The OP only has 3 weeks to figure out what will work, order parts, put it all together, and get the bugs out. How long did it take to build up your bike? How many trips to the LBS?

One was a 58 cm LHT and one was a 50 cm LHT.