and a yard of half-price fabric later...
here is the final product.
They were super easy to make, albeit a bit time-consuming. We got some leftover plywood from my parents' addition/renovation, and Stephen cut it to fit inside the lip of the crates (it doesn't seem like it would be very sturdy, but I was very pleasantly surprised!) I covered the plywood with some batting and fabric (lots of staples in each), and that was it! I still need to glue on a loop of ribbon to make it easier to pop open the "lid", but it's easy enough to take off the top without it for now.
Not so attractive from the bottom side, but luckily that part is hidden! I haven't decided for sure how I will use them in my room. I have tossed around ideas of using them at the listening center (with the listening books & tapes stored inside), at the computers, and around the small group reading table. For now, they are living at the reading table.
We will see how they work there in a month or so when we start reading groups. I still think they are the cutest (and easiest) project... and so useful for storage, too!
Happy first day of school!