Would you be opposed to inexpensive throwers, that you wouldn't mind leaving behind?
If so, there's a plethora of cheap throwers out there--they'll stick in a variety of things, and you can buy them in sets of three, or so. I second underaged!'s recommendation about a piggybacked sheath. A quick Google search under "throwing knives" should produce a few dozen opportunities to get some cheap throwers. United, Gil Hibben, etc., make some inexpensive ones.
Do keep in mind any legal implications... it can be far easier to explain away an EDC as a utility item, but throwing knives might raise a lot of eyebrows. Thus endeth *that* sermon...
Whichever type you carry, be sure you practice speed-drawing and throwing per your two preferred methods (it might be a good idea to hit your throwers with a few spots of bright spray paint, or you can lose them in the grass). I'm sure you already appreciate that there will be enormous changes in finding, drawing from concealed position, stabilizing the grip, positioning, aiming, and throwing in a clinch situation!
A co-worker once claimed to me that he would sometimes wear a thrower down the back of his neck. When he needed it, he claimed he'd reach his hand back to his neck, pull out the knife, and throw it.
Maybe it was true. But when I tried it, all I did was fumble trying to find the thing and get it drawn smoothly. So I gave up any illusion of *that* ever working. Plus, the darn handle kept sticking up above my collar: how is *that* concealed?