Lots of the lower end mapping apps are stamp based tools. Dundjinni is probably the best of that class of application.
Dungeonforge can run under wine and is a nice little stamp/tile mapping program (though it has its own limitations...)
My tutorials: Using GIMP to Create an Artistic Regional Map ~ All My Tutorials
My GIMP Scripts: Rotating Brush ~ Gradient from Image ~ Mosaic Tile Helper ~ Random Density Map ~ Subterranean Map Prettier ~ Tapered Stroke Path ~ Random Rotate Floating Layer ~ Batch Image to Pattern ~ Better Seamless Tiles ~ Tile Shuffle ~ Scale Pattern ~ Grid of Guides ~ Fractalize path ~ Label Points
My Maps: Finished Maps ~ Challenge Entries ~ My Portfolio: www.cartocopia.com