SO Careers is a great way to turn your reputation as a contributer into job prospects. But what if you're not looking for a job, you're just looking for customers?
Many people come to SO and SF looking or assistance with specific problems. They post questions and get answers, but often even a perfect answer doesn't help them. They want their problem to be solved, and they don't have the skills to solve it.
Many of us make our living offering this type of help to others. Maybe its our day job, maybe we do it after hours to pay for a new computer. We clean off viruses, configure webservers, set up Beowulf clusters, etc., on-demand for people who don't know how to do it themselves.
And many times that kind of assistance is exactly what people are looking for.
Still, it wouldn't be appropriate to include a shameless self-promotion to your answers, or say something like "What you're trying to do is really hard, give me a call and I'll help you." This is a place for answers, not plugs.
It would be nice if there were some unintrusive but visible way to indicate that you are willing to offer personal assistance in solving specific problems. I already include some basic contact info in my about me section, but most people won't know to look there.
I'm not sure the best way to make this work, but I would suggest something in the user's badge that indicates something like "willing to help", or "direct assistance available", or something like that. Perhaps it could be tied to a for-pay SO referral program. I know I would certainly be willing to pay SO a referral fee for people who find me because of my answers.
Perhaps to limit the potential for abuse, I'd recommend putting in a minimum reputation score in the several thousand range before you can apply for the "Consultant" badge annotation. If you're not good at helping people, it would be difficult to rack up a significant reputation score.