I've been following this thread and the drop bar thread with interest. Have you thought of trying the RETRO SHIFT type shifters I have them on two of my bikes and love them. it is an excellent solution if you like to ride in the hoods and with use any number of down tube or bar end shift levers. I run / have run 7 speed 105 shifters on both 7 speed and 8 speed cassettes and my current favorite is a 600 7 speed shifting a 600 RD with a swapped in longer cage on an 8 speed cassette. crisp reliable shifting close to my hands and I can visually see my gear selection at all times. the front shifter is friction and thus easily trim-able and works for any FD double, triple ,mountain or road. I'm not sure how well these would work on a dirt drop style bar as I have never tried one. though I would like to try the SALSA COWBELL bar if I can find one.

the below ones I made my self and are not quite as nice looking as the RETROSHIFT ones. mounted to some compact cane creek levers(same as tektro) If you would like to try them out for a while PM me. I would lend them to you as the below pair are currently un mounted (I have made 3 sets) you would have to come up with the shift levers in what ever flavor you prefere. the 8 speed bar ends will work perfectly.

Royal