Touring - Best generator for a vintage touring bike with internal wiring?

Several of the high-end steel touring bikes, i.e., the Miyata 2000, Specialized Expedition, and Centurion Pro Tour, came with internal wiring, from the top of the downtube to behind the bottom bracket.

Does anyone actually use these for the generator they were intended to accomodate? Would this typically be the old style bottle generator? I remember I had one of these on my Schwinn Continental as a kid, and it seemed to incur a noticable drag. Is this true of most/all of the bottle type generators?

Thoughts?

The wiring for the expedition runs from the bottom bracket to the headtube to accommodate a bottom bracket dynamo. This style contacted the tire patch right behind the BB, and rolled much like a bottle dynamo, but not on the sidewall. I am looking for one for my expedition. I know they were made by sanyo.

as far as bottle dynamos go, they range from very good to complete junk. The high end ones (busch and muller S6) have negligable resistance, while well built and cheaper ones (busch and muller 6, jos) provide some resistance, but not all that much- definitely useable for commuting and dependable lighting.

The best design is the front hub dynamo, but as these are at the front end along with the headlight, the internal wiring becomes pointless, except for the taillight- if thats what you want to set up. E.g. The downtube wire could be connected to a wire running inside of a tubus rack to a small drilled hole at the rack top for the tailight mounting. This would be almost entirely contained within the frame/rack ...

I did fine this one (http://www.bikemania.biz/Bicycle_Halogen_Light_Bottom_Bracket_Generator_Set_p/usabrand_generatror_98-69.htm). I suspect their are others available.

Here is another, the Union Bottom Bracket Generator (http://www.yellowjersey.org/dynamos.html)