I don't know if someone has already posted about these (a quick glance in the search says no), but I just came across this site that sells basing stamps called Happy Seppuku. http://happyseppukumodelworks.bigcartel.com/ They also have "accent stamps" that are press molds for detail objects. Like they have a pirate ship themed one that has an anchor, a chain, some rigging, some hatches, etc, etc. Looked pretty neat.
I saw someone on dakka posted a tutorial on how to use them, so i decided to buy the flagstone and the narrow wood planking stamps. I'll post about how they go after I get them.