This might be a key point. To spec a 9s Shimano brifter in 2012, a company like Trek or Surly would have to spec no better than Sora -- even Tiagra is 10s this year. While lots of us will accept a Sora FD, I don't think the same is true of Sora brifters, especially on bikes meant for extended touring.

For custom builds, 8s is the sweet spot for touring & durability IMO. NOS 8s bar ends are still easy to find, as are good 8s chains & cassettes. 7s might naturally be stronger than 8s, but the gear has become pretty scarce.

A nice thing about the stock 520/LHT builds with bar ends is current freehubs' compatibility with 8-, 9-, and 10-speed cassettes. On the road, you could slap an 8s or 10s cassette on a 520 or LHT and shift in friction mode.

It's also nice that the LHT and 520 have downtube shifter bosses. Lots of current frames only have housing stops for the handlebar-mounted shifters. With downtube bosses on the LHT and 520 you have easy cable tension adjustment (critical with "shadow" derailleurs) plus if you do bust your shifter when out in the boonies, you can mount any old downtube shifter & keep going.