I received my DH 3N72 yesterday
And that thing is HEAVY! When I picked up the padded envelope I figured there must have been a catalog inside, but no, it was just the hub in the box. The spec says 558 grams, and the spec on my front road wheel says 640 grams for the complete wheel. So figure 558, plus 440 for an XM317 rim, and about 160 for spokes, that comes to 1158 grams for a wheel, over 2.5 pounds.
Now the lightest dynamo hub is the SP series at about 400g, lighter but not that much. A generic front weight for a decent hub is generally in the 125g range.
And let's add up the cost: $78 for the hub, 40 for a rim, 35 for spokes, for $158. And dynamo lights are generally not so cheap. The B&M lights start at $75 or so and go up. Shaped beams yes, but limited output. And no flash mode either, which is almost a requirement in NYC. It is what distinguishes a bike from everyone else. (keep the argument in the other thread).
Maybe the self contained single LED lights are a better idea. (Ducks for cover from the dyno light crowd.)