Gollik knives is one that I am thinking about buying from. He is here on the forum and he has a Facebook and website. From what I hear, great knives, especially for the great price!!! He is definitely worth looking at and talking with. Gollik says his turn around time is about 4 weeks, which is really good for a custom.
Colin Shannon at Shannon Steel labs made me a 6.5 inch blade out of Z-Finit that is pretty awesome! He is making me a 3V slimline machete right now. His turn around time is fantastic and he keeps you up to date every step of the way. On the first knife I got, the finishing on the handle could have used a tiny bit of work, but it was very minor.
Robert Martin at tearsofthesword. I have one from him and another on the way, which he is throwing in a smaller knife on the house. Great guy, also keeps you up to date on progress. Takes a bit more time than Shannon. His blade I have is the toughest knife I have, and I have quite a few tough blades!
Another option is look on the knife maker for sale area under fixed blades here. Take a look at what there is, at least 3-6 pages worth, and if you don't find something you like, find someone that you do, and ask them to do a custom. You'd be surprised at how good of deal you can get a custom for.