Weight can be solved by ingenious body design and some inventive routing, i think. The hollow body might also warm out the tone some.
Regarding the sound, yes, of course pickups and preamps can overcome brightness. Just check out the carbon-fiber crowd. Zon, for example, uses a lot of bartolini, which are traditionally very warm pickups. I use dual-coil barts, which are 2x warm. And they make my Zon, which should sould even BRIGHTER than a maple/maple/maple bass, have quite a respectable low end (though i can eq it in a way such that the high end will slap you in the face)
IMHO, its easier to EQ frequencies OUT than to EQ them IN. Bright basses rule, you just need a good EQ.