I found this site a while back and was SO impressed. Honestly, I did 'Fairy Gardens" for my wedding centerpieces, but they were not at all as elaborate as these little living gems.
Take a look through the site, Little Landscapes, to see some of the amazing mini garden's they offer. Honestly, my thoughts on these are to make them yourselves. I would think if you have some little ones they'd LOVE the thought of planting and making mini gardens with you.
BUT... I'm too much of a kid to resist doing these on my own (I'll let my cats help, maybe).