I guess it all depends on your definition of shortcake. My mom's shortcake was more like a sweet biscuit. I've also used the "dessert cups" that are sponge cake that usually start showing up during the spring.
My definition of strawberry shortcake cupcakes would be yellow cupcakes topped with whipped cream and fresh sliced strawberries, but that's just me. I suspect if you polled 100 bakers, you'd get 100 different definitions.