Converting a Gary Fisher (made by Trek) mountain bike now... Not a 29'er though. If yours has disc brakes make sure you get a rack that will work with them (passing along what I learned on here). Check out the Ergon grips, love the ones I just put on my bike. You can adjust the grips and bar ends independently of each other to get a fit you like. No need to change brake handles or shifters (although you might have to move them a bit on the bars) I haven't ridden my first tour yet... but before I got my road bike I put a LOT of miles on my mountain bike (with semi-slicks) on it. My only regret.... I wish I would have had the Ergon grips!!
Still don't know what I'm doing...... but still I'm having fun doing it....