Hey R-E, thanks, those Op-Tech Fast Caps look pretty interesting, but I suspect they are mostly incompatible with hoods and wide angles. But they can be rotated to any angle, it appears, so I wonder whether they can be flipped back underneath the lens (and stay there) to avoid flash issues.
I think I might try a couple (they are pretty cheap on amazon.com). And also maybe pick up some cheapo step-up rings and screw-on extension tubes to act as hoods on my tele lenses, then attach these caps on the end of those. I wonder how well that will work.
I'll report back.
What was that I said about not overcomplicating things? Oh well.
Thanks for the input, everyone.