Wow, superb results. Love the fisheye shots on the sports camera.
My current ultra cheap wide angle setup is a G7 + 8mm fisheye. I defish in premiere by adding -27 in the lens distortion plugin, final results look very much like an rectilinear ultra wide with useable resolution since I can capture in 4k. The only downside is the excessive render times when using the lens distortion plugin (3 hours for a 5 minute 4k video).
If TS wants to toe dip into getting a fisheye, there's a 6.5mm Meike fisheye lens for US$140:
http://www.ebay.com/itm/Meike-6-5mm...6100-Cemera-/192178223398?hash=item2cbeb6f926
You needn't worry about AF since the depth of field is very deep