I've not ever been able to find how long the knife was that was used in the Croc movie in any official release by the movie studio, though many companies cashed in on the movies popularity with a plethora of their own versions later on. It was made of aluminum by an Australian movie prop man who's made various knives used in movies like Mad Max, etc.
It appears to be about 12-13" in blade length, and the ones I actually carry are 10 and 10 1/2" in blade length. I do have two knives that are 12 and just under 13" in blade length, as shown here in this picture.
The second and third knives from the top are Bagwell Fighters. The blades measure 11 1/2" long.
The 5th knife from the top measures 12.75" in blade length. It was made by a mountain man living in the Montana wilderness out of a model A leaf spring in 1930 or 1931. It's razor sharp, fully capable of shaving your face.
The bottom knife is the "Brown Bowie" as made by a custom maker in Pennsylvania from my own design. It was photographed at the New York custom blade show back in the mid 80's and featured in one of the national knife rags shortly thereafter. It measures 12" on the blade length, 2 1/2" wide, and a full 3/8" thick, flat taper grind to the tip and is 18" overall in length. I had the blank of D-2 carbon tool steel custom made for me by Jessup Steel also in Pennsylvania. It contains 12.5% chromium making this knife fully a carbon tool steel blade, and just 1/2% shy of being stainless steel.
The mountain man Bowie and the "Brown Bowie" would be roughly the same size as the Croc Dundee prop used in the movie, but they are much too large to carry for most even in custom sheaths. A knife that's much over 11.5" in length is going to be strictly a show piece and too heavy to actually use effectively for SD with the exception of the Bagwell Fighters. These Bagwells are so well balanced that if you close your eyes on the two in the picture and I handed them to you, you'd think you were just holding the handle and there was no blade. Light and fast, they'll reach out and tap you from further than you'd think in less time than it takes to blink.
The ones I carry and the two Bagwells have custom River city Sheaths by my buddy Mike Sastre. They can be concealed under a T shirt, you can sit, stand and move around all without noticing the blade all day long in his sheath systems and be drawn from concealed as fast as I can draw my handguns from under the same T shirt. I'm limited to about 10 1/2" of blade length maximum comfortably based on the length of my arm and torso.
I've presently got another Bagwell Bowie on order [ 14 month delivery time due July 2010 ] that will be 10" of pure fighting knife I'm going to carry regularly when I get it. This one will be 5160 tool steel and with a stag handle and brass guard. It'll be a working knife carried daily as I'm retiring my 5.5" custom Rob Patton knife as soon as this one is delivered.
It wasn't that long ago I was really into the blades and professional training in how to use them for SD with two of the best blade masters in the country. Now I'm just a little old man