Not sure if this is what you mean, but if you click on Limited Time Promotion in Behind the Scenes, they are doing a special on fixed sizes of stretched canvas prints. I've sold two so far. Here's the latest I have going --
http://fineartamerica.com/weeklypromotion.html?promotionid=157833
I specifically sized this one 2000X1600 since they are fixed sizes at 8X10, 14X11, 16X20, etc. etc. And then just for kicks, right now this is onlybeing offered through the LTP. It might not sell, but every LTP is a good reason for another post to social media or however you market your work.