For $500 I would agree that you can probalby get a knife custom made pretty easily. If you don't trust yourself in figuring out which parameters (such as blade thickness, thickness behind edge, profile, steel edge angle and so forth) represent the ideal trade-off I would go with a custom maker which has extensive experience with this, such as one who has competed in a cutting competition for example. There are plenty of such custom makers out there, and I am sure they would be happy to help you design your ideal user and build it for you.