Things which come to mind which appear to be variations on those already mentioned.
1. Any kind of key ring holder that fits on your belt. The knife can then be fastened to it in numerous ways such as paracord lanyard and some Swiss army knives even have a chain lanyard attached. You could combine this with a FastTex Buckle key chain system 98BKR1BK such as the BlackHawk Key Ring (3/4" inch), shown here:
http://store1.blackhawkindustries.com/cgi-bin/storenew.pl?page=new/fcatalog.html&setup=220&cart_id=
By the way Brookstone used to sell a stainless steel version of the key chain that comes apart, as was described above, instead of the usual chrome plated brass, but I do not believe they still sell it.
I recall using this belt/key ring system in Boy Scouts, where I recall it was part of the uniform. Clip the knife on by its bail, or metal loop, to the holder that was on your belt, and just suspend it in your pocket. I have used metal ones that are one piece (not solid) such as My Key Pal , ones with a dangling snap, a leather one that would snap on and off your belt with a dangling snap, and a Duty Key Holder from BlackHawk industries, 52DGKHBK, with a high quality dangling snap, as seen here:
http://store1.blackhawkindustries.com/cgi-bin/storenew.pl?page=new/fcatalog.html&setup=220&cart_id=
The duty key holder forms its belt loop with velcro.
2. Tie a lanyard to the knife and put tie a loop on the other end large enough to pass the knife through. You can then either clip the loop to a key holder or pass it under a belt or less secure belt loop, etc., and then pass the knife through it, and drop it in a pocket. Remember that lanyards can also get caught on brush and pull the knife out, but if fastened to something secure, that would not be too much of a concern. Once removed you can do the same thing to fasten the knife to your wrist, if you are more concerned with dropping the knife, then you are falling on something you cannot get rid of as easily. [Someone mentioned this concern about falling on a sharp knife that is attached to you, but there is no guarantee that you would not fall on it anyway if you dropped it at the same time as you fell.]
If fastened to a belt loop it could probably be ripped off if necessary for emergency access, but I do not volunteer to try this on my belt loops, at least not until I find a pair ready to be thrown away. You could make the lanyard any length and you could combine this with a fob system. Marions looks like it would provide emergency tinder.
Lastly you could get one of those springy lanyards, but I do not know how strong they would be. One is made for attaching Van Staal titanium fishing pliers, and is presumably reasonably durable, but the lanyard at around $16, somewhat expensive. The one time I saw one, it appeared to be made well.....they probably do not want claims that someones $200+ pliers were lost because the lanyard broke. It appeared to be just high quality soft plastic though with no imbedded emergency cord or wire. The idea is that it uncoils enough so you can use the pliers while on the lanyard. Not that tears are necessarily embarrassing, but I think the idea is to save one from crying, when ones favorite pieced of titanium falls in the water, hmmm...didnt this thread start because ones favorite titanium handled knife fell...... I plan on buying one as soon as someone gives me those nice Van Staal pliers

For those who just have to see what a pliers look like that cost

just a little less than a Sebenza, you can see a pair here:
http://www.basspro-shops.com/servlet/catalog.TextId?hvarTextId=27428&hvarTarget=search
I have the duty key holder and it is well made. It is somewhat stiff and I occasionally can feel the edges poke me when it hits bare skin, because of the velcro. I use it mainly for suspending my reading glass case from my belt when I have a t-shirt with no pocket. It seems secure and the clip is well made.
P.S. After posting I tried the links and the ones to the BlackHawk products from
www.tacticalnylon.com do not seem to go directly to the product, but you can use the product numbers to search.