I bought a few of those shadowboxes too and am also heartbroken that they are no longer available. Here is what Michelle's husband did with his collection. She also shares a simple idea for a sensory table for infants.
Michelle says, "I thought I would share some art that my husband made using old Ikea shadow boxes. Unfortunately, the shadow box is now discontinued (sigh) but it was able to be used in many an art project between my husband and I when it was available. My husband, Matt Ritchie, used them to make 4 by 6 inch dioramas. Using hand cut wood acrylic paint, and the Ikea boxes. The boxes used to come with a heart or key inside, and were really hard to open since the glass in front was glued in. We had to tap (well, pound) the box on the ground to loosen the glue, and the glass would usually come out pretty easily. Anyway, I hope you like these little art pieces!
Rast sensory table
"I turned this little Ikea nightstand (Rast) upside down and excluded a shelf so i could add a small bin to it and make it a sensory table for my infant/toddler class. I put different sorts of sensory objects in the bin, like flour, dirt, sand, oatmeal etc, and the kids love to pour them from one cup to another. the shelf was just the right height for the toddlers in my class, and I made all four for way cheaper than one pre-made table. Then I used acrylic paint to add the flowers on the sides!"