edited - I just noticed that this was a multi-page topic. Nice work.
I'm a little late to this party... nothing new there.
I've got the keel out of my V17. The keel is composed of a single piece of 1/2" plate steel armature, with a lead 'bulb' attached at the bottom. The armature/bulb assembly was then 'encased' with a two-piece fiberglass shell (with wood 'filler' blocks), which was then back-filled with polyester resin. Quick, and dirty.
Over the years water made it's way into the shell (via damage caused by the trailer keel support), the rust caused the shell to swell and eventually cracked the shell (allowing even more water to enter).
I found that it was necessary to completely strip the keel down to the armature, and rebuild from the ground up using marine plywood, foam, and West System epoxy. I'm still working on it.
Since I was going this far I decided to re-shape the blunt-edge thing with a 'proper' NACA0012 profile (I did this with my rudder and picked up 1/2 point to windward, and much quicker tacks). The trailing edge isn't as sharp as the 0012, but it is much sharper than the original keel.