Yes, there are, but I wouldn't get one. I especially wouldn't get one for someone who isn't a fairly experienced shooter with pretty high recoil tolerance. I'm assuming your wife falls into the latter category, since she hasn't already told you what to get her.
Little bitty guns are hard to shoot well, even moreso if they're chambered in something like .40 S&W. I know you're looking for ammo commonality, but a gun that's uncomfortable to shoot and perhaps even intimidating is not one she'll enjoy. The difference in "stopping power" (whatever that is) between the .40 and 9x19 is non-existent in the real world.
The PPK/S is actually quite large for a .380; it's the same size as (or even bigger than) some modern 9x19 guns, like the Kahr PM9, Ruger LC9, KelTec PF9, etc. The PPK/S's long DA trigger pull is typically 10+lb and gritty. The DA/SA transition can be difficult for many shooters. Since it's a blowback, the recoil can actually be a bit harsher than the 9mms, which are all locked breech. They are typically thinner than the PPK/S, which is critical for concealment.
There are many better choices, but if she looks at everything else and still wants a PPK/S, then that's what you should get her.