Check out the arm in the second picture here: http://www.thingiverse.com/thing:720139 Trust me, no flex at all on that arm.

I've tried all kinds of cameras and transmitters as I have a lot of quads (you can never own too many!). For just flying, my favorite cam is: http://www.securitycamera2000.com/pr...ra%252dUS.html

For 1080p video, the Mobius (make sure you get a genuine one!) is great. It's way lighter than a GoPro.

I remixed this a few different ways for my camera mounting depending on which camera. Also I turned it into a tilt only gimbal: http://www.thingiverse.com/make:137056
You just can't go wrong with a tilt gimbal. Without it you either end up looking at the ground when you're flying fast, or you use a wedge and you're looking at the sky when you're flying slow...