I'm looking for a swirly piece of Mac Eb from Rami right now. I'll let you know if we find any. It's typically straight grained. The other option is Ziricote. I don't have a photo of that wood right now, but I can describe it as Macassar Ebony colors, grained like a slab of picture jasper - like rolling hills. It's stunning. The Stanley Clarke bass we made for Steve Jay (Weird Al's bassist) is Ziricote, you may be able to find a photo of him playing it.
The Coco Bolo pictures I posted in the wood section have a scale marked off in 6 inch increments. There's quire a few that will do the bookmatch to center.
The side omegas would need to be fairly small, as there isn't a whole lot of room between the edge of the bass and the pickups. I tend to agree with you on the pistol grip, but I'll bounce some stuff off my mom and Mike as well, they are creative enough to make it work if it can.