Why not attach the mosaic to wire mesh.  Lay mesh over top of the pot and cut it to size.  Next cut a circle in the cneter large enough for the plant(s?).  Then cut the fitted mesh in half.  That way when you need to water, or transplant, you can lift up half the mosaic top.

I've seen those mini gardens too.  I'd love to have something like that inside the house but I know the kids would end up using it for play.  Probably find a mini Spiderman or Dora relaxing on the furniture.  I guess they're entitled to down time too though.

That's a great idea! (I'd probably have to water from below, huh?) I've seen these box-like containers at a local garden center that are filled with moss-covered dirt with some very small plants. In the middle of it all they have miniature garden furnishings like arbors and benches. Kind of like gardens for playhouses. They're fabulous, but I'm afraid I'd kill the plants. Plus, I'm not sure where I'd put such a thing!

It is pretty cool, I will admit...until a stray little weed pops up and you're forced to rip out a chunk of the stones to fix it. 

You know Maven you could do the top of the dirt like you did your flower pot.  Make a little mosaic on top of the dirt with broken pottery chips.  It would probably look like a mini flagstone patio.