The problem: every once in awhile, if I shift into my highest gear while spinning out - the chain is slack - I'll drop the chain off the outside of the chain ring.

I have a 1x8 configuration on a road bike using a cheapo single chain ring, the kind where the drive side crank is solidly welded to the ring. On front I have the ring, the chain, and nothing else. This works fine and I never drop the chain inside, just rarely outside if I don't keep some tension on the chain. I shortened my chain slightly thinking it might add some tension, but that hasn't worked. I don't see any way a bash guard can be added to this ring and crank, but correct me if I'm wrong. S-Ram makes some very expensive solutions for track bikes I think, but I don't feel like splurging on this.

I know I could put an old front derailleur on and that would probably work, but that's a little goofy even for me. So I thought I'd go to the hardware store and get a P clamp for the seat tube and a short piece of steel bar or long bolt, and just bend it back over and outside the chain just a few mm from contact. Or maybe just two p-clamps, one for the frame and one for the chain, mimicking a FD. Before I experiment though, do you think that will work or would it risk ripping things to pieces? Is there a reasonable off the shelf solution? Maybe a chain tensioner I can install on front?