Picked up one of these video out boards for the gopro.
Only basic testing so far, but i have not had any issues as some people report when using the side usb video out. No lag or lockups at all. Plus it charges my camera while in use.
Only issue right now is the large amount of screen real estate the gopro osd uses. But i think that can be disabled.
5000mah battery -> jst-hx to jst harness (sometimes called a lighting harness) -> Power filter (remove ESC/Motor interference) -> immersionRC 600mw vTX –> gopro
Here is the gopro 3 black OSD displayed on a 17″ wide screen car lcd tv. The resolution settings really make a difference on how good it looks. Need to make sure the ratios match between display and gopro output. I.E. 16:9 and 4:3
purchased from getfpv for around $20. Website reports this back 30pin port is the same on all series of gopro, but i havent tested.