I've got a fixie, but would like to do some long hilly rides - like SeattleToPortland coming up this summer. I think gears might be a good thing. I think geared hubs might be a good thing. I could just replace the wheel when I want gears, and then fix my bike again when not doing long distances.
I know, I know. Suck it up and get stronger. Take that fixie the distance. Well, I'm not there yet. Besides, I think it'd be fun to check out an internally geared hub. So, down to some details...
126mm spacing in rear
26mm diameter bullhorns (going to have to shift the thing with a shifter somewhere)
It looks like the Shimano Nexus 8 won't fit (130something spacing). Thoughts? I'd like to be able to swap a geared hub wheel in/out of my current setup. I don't know that I need 8 gears (though that might be fun too). 3 might do, if it had somewhere over 200% range.
for shifter... maybe downtube, or if you dont use reverse levers you could use a bar-end shifter. etiher way you should be albe to make it work with a friction shifter.
maybe you could get an old 3 speed or something, they are probably spaced small enough, you if its 130mm you can easily spead the frame (centurion is steel right?).