It seems to me that there are several threads regarding recharge of a battery system via the white wire- in theory, it should be possible. As it stands right now, one person has claimed success running a single headlight. There are several advantages to a 12 volt system, not the least of which is the avaliability of 1156 and 1157 compatable LED bulbs... a bit spendy, but not as bad as some systems I've encountered. The sockets for these bulbs are redily avaliable as well, and housing is left to the imagination of the builder (BWAHAHAHAHA!!!!)... however, I am to understand that the white wire will not have the poop to charge a 12 volt battery regardless of how you rig it. Mind you, I do not have an Electronics Engineer degree to verify this, but several members here and the other forum agree on that point.
Therefore a 6 volt LED light system would be the weapon of choice to start as a platform for a recharging battery operation if you MUST utilize the white wire- at least, that's what I am hearing from several corners. To me, that can be developed independantly of said charger without too much issue... and might well hold it's own weight without said charger. Run the contraption off four 'D' rechargables and get a recharger for them. You invest in two sets, one charging while the others are in use. If you REALLY do long distance at night, get three sets so you have a spare set go with you just in case.
THEN... there comes the day when somebody who is quite brilliant (or bloody lucky) creates the perfect charging solution useing the wretched white wire. Your 6v system will likely be compatable with it. Magneto tops the battery, battery pushes the lights- what could be more simple? Untill then, the regimen I have described will suffice nicely.
BTW- currently working on cable-actuated switches for brakelights. Will let you know if there's a breakthrough.
the Old Sgt.