The entire point of a custom build is that you know exactly what you want, and the only way to get it is to have it built for you. If what you want exists off the shelf or even in the used market it's going to be MUCH cheaper than a custom build, and without the 1+ years of waiting.
Yes, there are many luthiers who can build a headless bass with whatever specs and features you want. But what YOU think is comfortable or ergonomic might not be what the next guy thinks is comfortable. And if that's your question then literally every single luthier on the planet is going to tell you their basses are easy to play. Nobody is going to hand you a slab of unfinished wood and say "Hey, I never promised ergonomics!"
Before I had my first custom bass built I played literally dozens of basses, from $100 pawnshop basses to $10K+ Foderas. I took notes on everything I liked and didn't like, every spec, control, and measurement. It's not just about what the bass does, but how you play it. An ergonomic bass for someone who loves Flea and wants to smash the crap out of it as hard as they can is completely different from a bass designed for someone who wants to sound like Matthew Garrison and plays with a super light touch and a lot of finesse. An ergonomic bass for someone with basketball player hands is going to be completely different than a comfortable bass for someone with small hands and arthritis. Hell, even your idea of what counts as "heavy" may be different than the next guy.
If you just want to gamble three grand and cross your fingers on getting something you like then sure, we can give you a ton of names of great luthiers and any one of them can take your money and make a cool bass for you. But if you actually want to invest in an instrument that's going to be your #1 player for the next decade then you have to do some serious homework.
