USDA recommends that you use clearjel rather than starch (cornstarch or wheat flour) when canning pie filling.
I don't think I've seen them in stores, at least not lately, but I do see 3 cup (24 ounce) Ball canning jars on Amazon, but not at a price I'd be willing to pay. There are some 20 and 22 ounce jars, probably from China, on Amazon, but the reviews on them aren't very positive and the jars may not be compatible with Ball/Kerr lids and bands.