I'm updating this thread as I think it may be helpful to people looking to purchase a non-DSLR camera, especially people who really don't know what they're doing -- like me.
The e-Bay Canon A720IS new-in-the-box sale turned out to be a classic bait-and-switch scam; I'm just happy I got my full refund.
This put me back at square-1, which meant a LOT more research.
As it turned out, not getting the Canon cameras was a great thing. After reading all the camera-related threads at BPL, and many of the threads here, I realized that my priorities going into the search needed to be revamped.
Most notably, it finally sunk into my head how important wide-angle is for landscapes, which is pretty much what we shoot the most. And the Canon A710/A720 starts out way too narrow, 37mm IIRC.
My wife & I hike together, and we've got a lengthy once-in-a-lifetime trip to New Zealand coming up. Other than the NZ trip, we're most often hiking in BiBe. Two places that are pretty much all about landscapes. We've found that 2 cameras allows us to wander separately, never be without a camera, and also helps guarantee that we don't come home without at least some photographic evidence that both of us actually exist & were on the trip together. We've been using a Canon A710IS. Fine camera, but we only have one, there's a small hairline scratch on the lens, and some of the symbols on the backside have rubbed off, and it has unacceptable wide-angle capability. The other camera is a Canon SD500, which is not as good as the 710 in all respects and doesn't even have IS. Fwiw Tess is a good photographer, and I am more in the "even a blind pig" category.
So, after further education, here were the revised requirements:
1) must use SD card (that meant no Olympus or Sony)
2) prefer camera body to weigh <7oz, but would consider <9oz; absolute line drawn at <10oz. In addition, both cameras need to be compact physically.
3) At least 1 camera must have 24mm wide-angle, other one has to have at least 28mm
4) One camera has to have notably good macro; the other has to be at least decent in this area.
5) At least one camera needs good optical zoom out to about 140mm; the other camera has to have some kind of optical zoom.
6) Both cameras should have fully manual controls, especially the ability to move the focus point to a specific spot within the frame.
7) At least one camera, preferably both, should have about 8-10MP on a small-size sensor (approx 1/1.6 - 1/1.9, not 1/2.3 or 1/2.5)
Both cameras need a functional viewfinder of some kind.
9) Vastly prefer that the cameras take AA batteries
10) 2 identical cameras would be the ideal, but, if not, then the same brand would be good. If not, then really intuitive menus & excellent ergonomics become a major priority, as Tess & I will trade off cameras every day if the cameras are of unequal performance.
It became obvious about halfway through the research that we would end up with one "hobbyist" camera and one "zoom" camera. It also became painfully obvious that optional viewfinders and/or no viewfinder would have to be in play, as well as non-AA batteries.
Cutting to the chase, the "hobbyist" camera choice pretty easily narrowed down to the Ricoh GX200 or the Panasonic LX3. I chose the Ricoh due to the extra 12mm of limited zoom, the killer ergonomics, and the excellent (although optional) viewfinder. But I could easily have chosen the LX3. Neither one really screamed "I'm the one!"
The "zoom" camera also worked out to a pretty short list, and I ended up choosing the Panasonic ZS-3. This was, frankly, an unenthusuastic choice - in particular I'm really unhappy that it has almost no manual controls, and no viewfinder, but it did beat out all of the contenders, eventually. Maybe I'll love it.
Panasonic ZS3: http://www2.panasonic.com/consumer-electronics/shop/Cameras-Camcorders/Digital-Cameras/Lumix-Digital-Cameras/model.DMC-ZS3K_11002_7000000000000005702
If I end up really liking or disliking these guys I'll update again...