The NYT has a good review of boutique or concierge medicine. I was surprised by how relatively low the concierge fees are -- $1000 to $2000/year (For a reasonably wealthy person this is not much money.) One the other hand, if one also gets insurance payments for the visits and services a 600 person panel this can make for a pretty decent income.
I don't see patients any longer, but personally I preferred taking care of the non-wealthy. Still, one could mix a 'concierge practice' with 1-2 days a week of charity care (forget the insurance companies for the non-wealthy, too much hastle).