You could check out Rocky's Custom Clothes up in the SF Valley. They did mine; you will need to have a clear idea of what you want (they cater mostly to people looking for a kind of flashy style), but I think they will do a good job as long as you are clear about what you want. They will do the measurements in person, and will take care of making sure the fit is good after the suit is made (the actual clothes are made overseas). I think you'd be looking at about $700-900. There's another custom suit place up there also, but haven't tried it. Kent Wang has also said that he can do a dinner suit.
Online, you could try Black Lapel (MTM; you can specify less fashion-forward options than their defaults, for instance, widening the lapels a bit, but they only offer satin facings, not grosgrain), Suitsupply - their off-the-rack offering looks decent (single button, wide peak lapels), and also a somewhat slim cut. Suitsupply also seems to be one of the few options for a slimmer pique bib-front formal shirt. Haven't tried it, but wish I had come across it sooner (I ended up getting Thomas Pink's - their slim fit formal shirts are a bit expensive, but fit me pretty well, and I'm a fairly skinny guy).
Most good MTM places should be able to do something pretty close if you give them a photo of what you're looking for. Compared to the RLBL, I would consider nixing the flap pockets (even if they tuck inside) in favor of self-faced besom pockets, and maybe do ventless instead of double vent.
Agree with the suggestion to try to go for something with a higher rise and not too tapered a leg.