This Williamsburg, Brooklyn MD specializes in 18-40 year olds without health insurance. He accepts no insurance and instead charges an annual enrollment fee for anytime access by mobile phone, email or IM, with rates he says are much better than you can get anywhere else. He promises personalized referrals and same-day or next-day house calls(!) .
I appreciate his efforts to innovate and work outside the system. If I didn't have health insurance I might think about it. It would be especially great to be able to see a doctor right away.