Someone left a comment on my site a while back linking to a picture of how they do it in India. In the floor of the kitchen was a depression that the spices go into. Then an oblong stone is rolled back-and-forth over it until the spices are powder. Very similar to this native American one --
http://hearstmuseum....ery_1_4_1_11.html -- but no lower platform, just built right into the floor.

For a more mortar-and-pestle style, there's this one -- http://commons.wikim...rinding_stone.jpg -- which looks to be built into the counter. Makes your Thai one look like a toy in comparison.

One I found -- not the one I was looking for -- that shows the grinding surface built right into the floor: http://rajirules.blo...9/04/floored.html

There are apparently still women who make a living going house-to-house grinding spices for people, one week's worth at a time. And they go through a lot of spices.