Lowell, I do agree with your viewpoint that it's not so much a backup as an alternate, but I guess when compared to some folks, my alternate is the backup---I travel a lot, and photography (as if you couldn't guess
isn't how I make a living. So, while it would be a bummer to be without the dSLR, I also don't have that need to make sure I travel with a spare body.
As was said elsewhere in another thread, a photo by a P&S is better than none at all.
So when I am considering it as a backup, to me its something with a tiny footprint which can step in should my k10d go down (again), so that I am not totally without images from a trip.
I managed last week because it was only DC, and I can and will be back plenty of times. I can't say that Ill be to Zagreb or Moscow a lot after my business trips, so not having any camera would kill me.
The camera guy at the local shop was trying to get me on (i think) an Olympus 1020. Then when I said "lower price", he offered up a gently used Olympus 770 (I believe). The 1020 was nice, but too expensive. The 770 wasn't bad, but looked more than a little used, plus it's over a year old. For a bit more, I could get a recently released CoolPix, which seems to meet my needs.
Brand-wise, I think I am down to Nikon, Olympus and Pentax. Honestly leaning toward Nikon, because it would use SD, and seems to be a bit better (and more affordable) than the Oly or Pentax offerings. The only drawback with the CoolPix line is no rechargable batteries, but that might not always be seen as a negative.
Really think I am narrowing things down to that one CoolPix I sent a link for.
If it was a trip-of-a-lifetime type thing (ie, safari or a return to Tahiti) then a second dSLR body would be on the list, if only as a rental. But now, I can be happy with the alternative