And this turned out to be the perfect solution!
I got small little buckets (on Amazon, a dozen for $15), painted them roughly in our living room colors (yellow and grey) with paint we already had, filled the bottoms with pebbles, fill the middle with soil, got some tiny succulent cuttings from our garden, and popped them in. D punched six nails into the wall, and we hung them up. Total cost = $15, total time = under an hour.
Aren't they precious? Looking at this picture from two weeks ago when I just hung them up (i.e. when they were freshly planted and rather droopy), and looking at them now, I realise the succulents really are growing! Especially the middle yellow one; he's all spiky and vibrantly green now. I love succulents because they are so idiot proof.