These fit the bill perfectly:
https://hobbyking.com/en_us/mobius-w...video-out.html
Surprisingly good video for the price. People use these on racing quadcopters as they can take a bit of a beating to boot. Runcam makes a similar camera, probably based off the same design.
I bought the one in the above link and can have been impressed with it. Only downside to consider is I don't think they don't have quite as many mounting options as a gopro and I don't think there are any waterproof cases for them.
All that being said, the GoPro sessions look amazing, I would hesitate to buy one. Especially with that variety of mounting options for them.