Being that I don't sew, don't own a sewing machine, and pretty much remember that when I did sew (back in middle school) the results were not good! I would say if I get brave enough to try out sewing, this might be a good first project.
This YouTube video I found makes it look easy, just like the shows I watch on HGTV where they make it look like it only take 40 minutes to redo an entire room. If you have no sense of adventure, maybe you could send your bags to a crafter that makes them since I also noticed people selling these on Etsy. Whether you buy one of Etsy or make one yourself, it is a great way to keep dog food bags out of the landfills for many many years. Although I don't feel ready to take on this project right now, I am saving my dog food bags and thinking about different projects I can use them for. If I do make a dog food bag tote, I will surely post it! Anyone else have ideas on ways to PUPCYCLE dog food bags?