I have been using MCmap with MCmapDZ to add a google maps style interface. It renders blocks it does not recognize but the colors are not correct. It is good enough to make out the terrain and figure out where things are.
You can see in that sample the giant redwoods are gray as well as some of the Autumn trees. For now it is good enough for the players on my server.
I know you can give it a colors.txt file to associate block id's with the correct colors, I just have not taken the time to do it yet.
Hope that helps.