Jon,
I have been shooting with a Nikon D70/Ikelite Housing and DS-125 strobe. I freedive with this quite often but mostly in shallow water. I know what you mean about it being a bulky system to carry deep. I was recently on a 20m wreck and I wimped out and carried my old Nikonos with 15mm lens
. If you are trying to keep the cost down you might want to consider looking at Tokina brand lenses. They are considerably cheaper than Nikon and Cannon lenses. I have never owned a Tokina but I have talked to several serious UW photographers that recommend the Tokina 10-17 for wide angle. For wide angle, I have been shooting with a Nikon 12-24 lens. It is considered a rectilinear lens (unfortunately very expensive) but on its widest setting I can see very slight distortion. I always find myself shooting with that lens on its widest setting, and wishing it were a little wider, so I am planning on selling it and picking up the Tokina 10-17 fisheye.
