I'm about to try a set of 105 shifters on my tourer. Since the shifters aren't compatible with the current XT chainring spacing, I'll have to buy a new triple crankset and probably a front derailleur, too, although I'll give the current derailleur a try just to see what happens.

If I have problems with them on a tour, I'll just do the best I can with what I have, same as if I'd let the bike fall over and snapped off a bar-end shifter. Worst case: have the old bar ends shipped from home and ride on.