I made this for my Summit to do FPV as a spare body but there's no need for me to have two. It's basically plug and play ready for your Summit to get it up and running without video gear. The camera housing was made for a GoPro HD Hero 2 but could easily be modified to fit the original HD Hero.
It fits in place of the stock body posts in the same location and is a quick change from the stock body if you want to go back and forth. Just be sure to add preload to the springs as this body is heavier than stock.
Save yourself the hassle of having to square out the holes for the body posts and doing all the cutting and trimming of the steel and plastic to make it fit just right over the Summit.

$100 shipped in the CONUS.

If you want the GI Joe that goes along with it, add another $20.

What would have to be modified on the mount to make it work with a first generation GoPro?

The cut for the AV out would need to be made in the box on the bottom half as opposed to the top half for the HD Hero 2.
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Sold! Thanks RCG!