if i ever got around to actually, you know, getting a job i would most likely pick up a cyclocross bike, and then i would most likely put a front blinky on it in addition to the lights i already have on the bike which would bring the total number of battery pack on the frame to 3.

the problem is that if i had to fit 3 battery packs on the frame right now i don't even know if i could do it, and my current frame has relatively straight lines. but a lot of the new frames, especially from Specialized have a top tube that is aggressively curved which i think could be problematic for longer batteries like the one from Dosun or the ones from NiteRider Pro.

what would be your frame considerations with respect to being able to mount multiple long batteries ? i suppose internal cable routing would be nice - anything else ?