somehow I doubt KLM's inflight services are set up to deal with such queries!
It seems that someone is selling on a trolley they bought earlier this year:
http://www.flyertalk.com/forum/klm-f...sell-them.html
I hope our OP didn't pay much more than the €35 they originally went for.
Note: They may not be the originals, but it should be relatively easy to find some sort of plastic container (Blokker, Xenos, Ikea, etc) that would fit: