Last night, Artem tore down the APK of the new Play Store and found a whole bunch of upcoming goodies, including support for wishlists and gift cards. The first physical evidence of said gift cards has now landed in the hands of Android Central, showing off what we'll likely see soon in retail stores across the country.
That, of course, raises another question: which stores will sell these gift cards? Unfortunately, for that, we don't yet have an answer. However, we've already started to hear rumors that Google could be planning to release these cards, presumably along with the new features, around the end of August/first of September.
Only time will tell, but at this point, it's pretty safe to assume that we'll see this implementation sooner rather than later.