After a series of incredibly awful releases, I eventually gave up and just bought the program "EarthSculptor", which is an awesome tool. EarthSculptor still costs money, so I have rewritten my map editor entirely so that it is functional. It's a lot less user-friendly than EarthSculptor, but it's better than a paint program for making heightmaps and it's free. Makes use of shaders and FBOs, which ought to be ubiquitous.

Links to original release locations:
--http://www.pygame.org/project-Map+Editor-455-.html