Have you tried a titanium blade?
The closest I have come was a titanium coated gill rescue kife, which was fine until the serrations dulled, and it was cheaper to replace it than to resharpen it.
The problem with titanium blades is that they just don't take a very good edge, and dont hold the edge they do take very long. This is caused by the relatively soft metal. Though their non-corrosive properties, and light weight make an interesting trade off as compared to stainless steel, which doesn't take or hold a very good edge either.
My primary objection to the knives I have seen on the market is that I don't think they are very well designed for the tasks that they need to acomplish.
First of course is they need to be sharp, very sharp, because sawing away at a line to free your crew member with a line crushing his body just won't work.
Second they need to have a locking blade. This eliminates a lot of English made knives, since they have legal restrictions on them (or so I understand). To me this is a non-negotiable.
Third they need a marlin spike. I use mine more than my knife blade to be honest
Fourth a shackle key. Ideally this would be cut into the handle itself.
Fifth the knife and spike should each be capable of being deployed single handedly, by feel alone, AND be able to be collapsed the same way.
Sixth a solid way to clip the knife to a pocket
Seventh rust resistance
Eighth the ability to be resharpened on the boat, without the need for jigs
Ninth NON-SERRATED. modern lines like spectra/dyneema do not respond to serrated blades, and have a tendency to pull threads, not cut. Scalloped blades work quire well, but they can't be sharpened (or so my kife sharpener tells me).
Ten light weight
Eleven a blade tip that when dropped on your tow won't penetrate, so some sort of blunt end.
Twelve strong enough it can be used as a small pry bar. Nothing extreme, just prying up cam cleats that have been glued into place.
Somewhere I actually have an exhaustive list, but this is the majority of my criteria. Some are definitely, others I would be willing to compromise on, but some of the major failing is see are that many knives require two hand to open or close. How exacally am I supposed to use two hands while cutting away a sail on a bouncing foredeck? Lack a locking blade or spike (I have scars from both), and a lack of a shackle key.
I know I am picky about tis, but it just doesn't seem to me that knife manufacturers really think about what they sell to sailors. They just stick a spike on and call it a day. Well, I want something a little more elegant than that, and until I find it... Well I will just keep collecting dull rejects. :P