I am looking for information about setting up a retainer based medical
practice. I have read all that the web has to offer on the subject. 
What I want to find now is a conference where I can learn much more
about this
subject quickly.  Are there any conferences devoted just to the topic
of establishing and running a retainer based medical practice?

1.  This is not exactly what you asked for but I suspect that rather
than conferences where many different consultants give talks, the best
you are going to be able to do quickly is sign up for workshops
offered by consultants in practice building.  To get a list of such
consultants, you can go to the AMA site below and send email.


AMA Solutions
http://www.amaconsultinglink.com/ama/survey.htm

and enter information as to what your needs are for a consultant 


2.  Or you could call a Practice Consulting group directly.  They
often have workshops on weekends and booths at conferences.  Check
their web-sites for workshop dates/locations.  These were the only two
I found on the web that discuss boutique (retainer) medical practices.


1.  Medical Practice Startup Consulting

http://www.practicemgmt.com/


2.  Practice Builder's Services

http://www.practicebuilders.com/

1-800-679-1200 ext 235


I hope these links prove useful.