alt Hacker NewsI'd love to do this and have a quite marketable resume, but it is extremely, extremely, unclear to me how you build a clientele or where you'd even start.
Only road I can imagine is highly specialized industry, with money, that often has time-sensitive needs, and smart management that knows how to recognize value or trusts their tech management. And even then I think you'd have to start in the coal-mines version of it, $50K/year flat salary, and building a reputation without management taking credit for your successes, somehow.
The hard part is to get the client on the phone.
Once you have them on the phone, you can not only better understand their problem but also demonstrate your skill and credibility in a way no resume or branding could.
At that point it's just a sales game - generally you'd avoid hourly rates and sell them a solution (see my other comment) which will maximize your effective hourly rate while being structured in a way that's very good value for the client. Hourly should be a last resort, at which point generally you'd rather have the client bounce, so you quote a high rate.