thank you mister claycombe that cost me money, i now have a spyderco tenacious on order...
just a couple of general pointers, on handles and materials in general. carving can put a lot of pressure on your hand so you want a really big comortable handle with the minimum of pointy bits.
if you're using the knife outdoors, it doesn't have to be very cold at all before a bare metal handle starts sucking all the warmth and dexterity out of your hand and fingers. not what you want when playing with sharps. i would really strongly recommend staying away from the metal handles.
lots of people have problems with rubber handles causing hotspots and blisters. though, it's not something that's ever really bothered me.
of your final three options, i'd say go for the kbar mule.
my first choice given your initial set of requirements would be the spyderco, and i am
have another look at the photos in this review on BB
http://www.britishblades.com/forums/showthread.php?t=50313&highlight=tenacious notice how the cutting edge comes right up to the handle, that's a really good thing. the open plan handle makes for easy cleaning and hygiene. at about twnetyfive quid delivered it's a bargain.
my second choice would be a big locking swiss army knife with a saw and an awl. the ideal would be a one handed fireman if you can find one. ugly but really useable.
as far as the other options go, as much as i love opinels, they are superb cutters, but not at all my first choice for a folding bush knife.
cheers, and.