To rephrase your point Erik: "What is never more than arms reach from your body in the back country." This also implies what is on you.

My EDC is such that it is always within 3' of me. Either in my pack or on my body. An EDC is by definition something that is carried on the body.

For example: a solider has a large ruck sack with all the things they did for their time in the field. However on their person are things they will never be without if they drop their ruck or can't get to it. Some of these are on their vests or in a buttpack or in pockets.

That being said, My EDC is ON me not in my pack. Part of my EDC is a RSK Mk1, a leatherman and a small gerber folder, not to mention a B-52 can opener. If I am thrown in the water, run down by a bear, suddenly surrounded by ninja's, these items would stay on me, unless I suddenly started throwing off my clothes. If I lost one then I have a back up.

and oh yes, something like my RSK Mk1 would be dummy-corded to my body.

Here are three good ones, which are available at low cost on ebay.

The buck mayo northshore (BU-173)
http://www.knivesplus.com/buck-northshore-knife-bu-173.html
a solid liner lock with pocket clip for tip down carry, and only weighs 2 and a half ounces.

the buck mayo cutback
http://www.oregonknifeshop.com/buck-mayo-cutback-knife-174.html
a frame lock, pocket clip with tip down carry and weighs 3.3 oz. This knife often sells on ebay for under $20 and it's a bargain.

I've used both of the above extensivly hiking & camping as my main knife.

Boker trance.
just got one and i love it - although i haven't useed it yet! Mainly because it perfectly fits my hand. Framelock with tip up or down carry options. Mine is non-serrated, but it also comes in a combo edge if that's what you want. Weighs 3.1 oz. Blade is 2 & 3/4 inches long, while the two bucks are just over 3 inches.

The buck mayo hilo is a bigger version of the cutback; over a 3 and a half inch blade.

All of the above should fit your specs without a big outlay.

There's always the good old Buck 110.
420HC or S30V.