Also, the stock LHT comes with nice "touring" gears, 46/36/26 up front with 11 x 34 in the rear. Nine speed 11 x 32 and 11 x 34 mtb cassettes are readily available and not very expensive, the same can't be said for 10 speed, so if you want to maintain that sort of gearing it makes more sense to stick with nine speed. Nine speed chains are more durable than ten speed also, another plus for a touring setup (and eight speed is more durable than nine speed for that matter). If you really want brifters, it would make sense to just pick up some in nine speed, I believe Tiagra is available in nine speed and would be compatible with your current setup-