Are often the best. The program I transferred to (Temple, which is turning out to be an incredible program) never advertised an open spot. A friend of mine who couldn't get a prelim medicine program last year refused to go into the match and instead emailed 300 programs. He got a prelim spot at a great place which actually refused to interview him the first time around.
Make discreet inquiries, send around some emails, see what pops up.