I commissioned a painting to serve as the basis for my cover.* This was a little more costly than some other options, but I love old-style field and stream magazine covers and wanted something like that. Who knows when I'll author another book? Might as well get it how I want it.
I used Dustin Dattilio, an artist from VT. He did an awesome wood burning of a grouse for me a couple years ago. Check him out here: http://dustindattilio.wixsite.com/dustindattilioart
(Tell him I sent you)
So far, the painting is coming along nicely!
*Note for people considering this for their book- get a contract that allows you to do this. There is a gray area with a work for hire, but if it is set in place upfront, it can save you some headaches. Be aware, you may also have to pay for a reference photo and the license there, depending on your artist.