I've just built custom components on a LHT frame . 26 / butterfly / v-brakes.

Butterfly is preferable to straight MTB handlebars in that the front portion can be used to install accessories (gps / headlight)

As far as brakes are concerned, the frame determines which type you can use. LHT - > v-brakes, Disc trucker -> disc brakes. If you have not yet committed yourself to a frame, then you may agonize over which is best. I've opted for v-brakes but both systems have their advantages. As far as I am concerned, they boil down to rim wear vs simplicity. No meaningful difference in breaking power. I've opted for simplicity.