Last summer I did a conversion on my old Panasonic from stem shifting to bar-ends. I bought a pair of vintage Shimanos (with the spring) for $40 from a forum member. This was the best bang-for-the-buck upgrade I've done on any of my bikes. I simply love the intuitive feel as compared to the stems. I think I completely adapted to the new location inside of two miles.

As a bonus, I ran my cables under the bar tape as others have done (along with the brake cables) and it really cleaned up the looks of my cockpit. As someone else mentioned, I did have to buy a cable from a tandem to reach the rear deraileur as the regular length ones were a couple inches too short.

I've only knocked a shifter with my knee when climbing once since I did the conversion, where as before it seems I would smack the stem shifters at least once a day. Yes, I know this is really a technique problem but at my age I'm probably not going to fix my body mechanics.

I've ridden friend's bikes with downtube shifters and while I do prefer those better than stem shifters, I still prefer the bar-end location. Ultimately brifters are probably the way to go but are much more expensive and on my old beast would probably necessitate changing the deraileurs as well.