Out of my ukes, the two that are prone to dings are the Cedar top of my Pono and the back on my glossy Koa Kanilea. No dings on my other ukes, including another Cedar top as well as more from Pono and Kanilea. So I guess that the dings have a lot to do with the individual piece of wood, not just with a specific maker or type of wood.
Finish might add some protection, but with the two ukes mentioned, I think the dings are actually imprinted into the finish. Nevertheless, that wouldn't stop me from buying those same instruments again. And after the first couple of marks, I found myself handling those instruments more comfortably.
Like others said, you shouldn't be worried too much about the possibility of dings, but rather focus on what you and your wife like. Are you looking for a traditional sound and look, or something a little more Guitar-like? What playing styles will be applied? To me, the Kanilea is best for strumming, while the Cedar top Pono is more apt for fingerpicking, and the Pono AT makes for a great allrounder.
Speaking of a great allrounder, I'd recommend considering the KoAloha Opio line as well. Arguably the best sounding production Uke, in my opinion.
Which brings me back to the original topic of durability: Contrary to what seems to be a widely held opinion, I found that my satin finished ukes are less prone to scratches (but might stain easier from sweaty hands etc.).
Anyway, good luck with your search, and keep us posted on what you'll end up with...