Sorry for the late response my friend, each motion capture was done by itself then synced. there might be a way to attach a sony eye using a hat, but for that to not interfere with the body cap you will need to respect the face and hair colour, i dun even mind painting my sony eye.

Imma check the net for camera hats and see if this can be achieved, this will be interesting! One major problem though, while you move your head the background will keep changing, this will totally ruin the marker placements/detections, need to think of a way for future projects.

Has anyone considered using the Hero Gopro HD cameras? These I believe can shoot 60p at 720 or 1080 resolution and are not that expensive.
Any thoughts?

I have the standard edition. Unfortunately, it's pretty useless. I have spent a considerable amount of time with various setups and never got even semi-decent results (even when using 720p50 footage).
I guess the pro version can yield satisfying results (when used with 3-4 cameras) but its price is outrageous.