B,
That blue is great, but I don't think black stripes would do it justice. B/c the blue is dark enough (esp. if you go darker), I think you need something with some contrast and I don't think the black has that - it would just get lost. One more comment - the line of the strip leading into the seat doesn't quite sit well with me. From the side, I think it would flow better if the end of the stripe leading into the seat were curved into towards the center of the tank (from the top), so that it looks like it lines up w/the curve of the seat where it meets the tank. (Make sense? To me, it looks like the stripe is 1" below the seat level.) And, in looking at it, that might be hard to do. Almost looks like you would have to lower the front edge of the seat, rather than monkeying w/the stripes. Then that would open another can of worms. Hmmm...
Disclaimer - I always hesitate to give my opinion, as I don't want to appear as if I'm criticizing, so please don't take it as such. Your bike(s) are beautiful (mine is in nowhere the same state of polish), so it's more of my musings on what would make a perfect bike perfecter.
Peace,
G