got some info myself. It will be somewhat harder to enter a market you haven't done your training in, especially a region like california. Need connections and word of mouth to build a private practice to the point where you are making good money. It takes time and effort but it can be done. People are discouraging me from private practice because of the headaches and low income potential in the beginning.
As for surgery specialties, the most common type in my area is definitely plastic and cosmetic (California, go figure). The yellow pages are filled with them. A good number of ortho and urology as well. The least saturated markets are cardiothoracic, vascular and general.