Yet again, I owe everybody an apology for not responding to messages for awhile. I've been putting in some 12 and 13 hour days...

Thanks to all who offered excellent suggestions in this thread.

Some of them I'm still following up on, but, so far, two things have worked best.

It turns out that some "inside" front pocket change pockets do work for a clip- and a few do not. However, the suggested solution of a simple safety pin through the pocket layers works very well indeed- well enough to consider using it even if there is a change pocket. With the knife in place along the front edge of the front pocket, putting a largeish safety pin vertically, about half an inch away from the knife and about two-thirds of the way up, makes a nice little "custom" sleeve for it that both keeps it out of the way, out of sight, and still easily accessible.. even a surprisingly large knife. I do have to be a little careful if my knees are up- say, in a low chair or in the back seat of a small auto- but no solution is absolutely perfect. Especial thanks to David for the suggestion- if others mentioned it as well, thanks, sorry I missed mentioning you.

Two safety pins, or, to get really extravagant, a line of stitching, would also isolate the knife from pocket-junk wear, and allow use of the rest of the pocket for other (infrequently used- it's a little tight) items. For me, the lighter fits that description, and possibly the Leatherman Micra.