I have an actual HD underwater video system
Sony HDR-HC9 Camcorder in a
http://www.backscatter.com/sku/gt-hc7.lasso
with WP25 FathomWide Angle Port , and flat port etc.
and 2 sets of Niterider HID lights
http://www.leisurepro.com/Prod/NTR2040.html
but a little outdated, still works, but with the weight restrictions of airlines,
I will using a Nikon D800 underwater, since it does 36 meg still and HDV video.