Those seem to be the usual ways to generate income from comics. Mutts, for instance, offers large prints on heavy stock with an embossed seal that we've taken advantage of a few times. (They've still got the pixelated background use in newspapers, so they're not fancy copies of originals.) They have the usual T-shirts, etc., too, but having an inventory of such things can be risky.

I'm sure you've thought about all these things, though. :-(

Best of luck with the hunt.

Cheers,
Scott.