Hi,
I have seen in the grocery freezer section these types of things. My memory suggests Pepperidge Farm may do it. I cannot advise whether they taste good.
IF you are making homemade filling, then why not investigate making these shells yourself. Maybe by making pie dough, cutting it into 2-inch circles (experiment, I am guesstimating), then stick them into mini muffin pans. If you are prebaking the shells, then put some foil inside and add some beans to keep the shape you want while they bake. Later, you pull out the foil-n-beans, and return it to the oven to finish baking for 1-2 minutes.
No commercial pastry shell will enhance your homemade fillings, though I suggest your homemade pastry and fillings may be a winning combination. Why not make a sample batch to test for yourself your ability to make these shells ... you know you can always buy.