As to your theory about everything being in one place...I heed that concept for theft but not for loss. I don't worry much about theft in the woods. As to loss, my knife rig is the only single item that will never leave my side....the only true "From my cold, dead fingers" item that I carry into the bush.
Regarding 'crazy sheaths' or whatever, my experience has been different from the OP's. I have a number of multi-functional sheaths for some of my bush/survival knives. I've always carried a stacked leuku/puukko sheath on bush trips and have several sheaths for other knives that I have modified over the years---usually done around a campfire out of boredom and with whatever was available. Results in some unique sheath mods....
One example---my HEST II Woodsman, a fine leather, full snap-flap sheath: I incorporated my SeberTool case (leather) by stitching it onto the sheath flap (perfect fit) with an awl...this carries the Sebertool and a set of slimmer tools slid in behind it---a coin w/ 5 screwdriver blades, as well as an armoured magnifying lens---both in turn attached to the case by thin leather twines to prevent loss. It doesn't impede access to the knife at all as everything sits tightly attached to the sheath flap. I unsnap it, lift it.....snap the whole package back closed. When I work out of the SeberTool case the knife flap remains snapped closed and undisturbed.
Behind this, at the top, I rigged two leather-loop hang points mounted for anything small I might want to temporarily attach by caribiner for immediate access.
On the blade part of the sheath I have a mini-buckle leather strap cinched around the center area to hold smaller slip-in items to momentarily free up my hands or carry something; looks good when it's empty too. Also, via some leather lacing (also providing for the usual basic "emergency cord" be-prepared B.S.)wrapped to enhance the look of the sheath, I've hung a draping loop of copper biker chain which drapes the face of the sheath (also looking damn good) and makes an excellent gravity holder for my fire-steel or small flashlight when tripping around camp or anything else I need to secure there for a few. I added two brass hang points to this area of the sheath as well---one a keyring-type, one a D-ring. Like having a couple of gear magnets:
Say I'm standing in a trout stream up to my knees, catching browns all day long wearing only cutoffs, a belt and my HEST II rig...using the SAK I also carry to gut em as I catch em....no place to lay the SAK down for a second as the little bastard fins me and squirms around. I clip its lanyard to one of the hang points on my sheath, the folder dangles while I do what's needed, then unclip it and have it back in hand. A lot better than closing it, putting it in a pocket then having to get it out and open it again while holding dangerous wild game in the other hand.
In winter? The first thing I do when I need to remove my glove(s) for something---clip the glove clips to a hang point on my sheath. The gloves ain't going anywhere even if I get distracted now. And if it warms up they hang beside my sheath all day. So what?
Anything attached to my knife sheath will NOT be lost.
I also rigged my Camillus USMC sheath to carry my Ka-Bar Acheron piggyback when needed and it's very handy.
Bottom line, IMO being able to secure items to a sheath quickly can prove useful in many ways throughout a day in the woods.
EDIT: I like those little ESSE packs that attach to the smaller sheaths too. Perfect for what we are talking about.
Photos !
