Hi again,
Turns out my idea had just about every potential problem I had thought of and some I hadn't. I also couldn't get Ron's idea to work (at least, not in LTSpice), but I did manage to get one idea working. See the attached image. The other attachment is the LTSpice file if you want to simulate it.
Note that this idea works (or is meant to; I haven't tried it in the real world) on power-up only; that is, when power is applied, you get the LED on for 2 seconds, after which the LED should flash for 0.1 second every 3 seconds until you remove power. It should work with a low-going trigger if you remove D4, R9, and C3 and just put the trigger into the left side of C5.
Anybody have any thoughts? Too complicated? Seems like there must be a simpler way to do this.
Anyway, that's my idea. Hope it helps!
Torben