Ok, it seems I've got some free time and inspiration to resume my work on KaM Editor
Here is the most recent version 0.3b:
Whole thing is coded in Delphi+OpenGL, so you should expect good perfomance.
Incase you have any bugs found - please report me asap.
P.S. What map editing features are most important for you ? (don't say a word about scripting yet )