This crash took longer, I think because I didn't do what I usually do, which is to take 8 heroes off their horses, save the portraits, then put them back on the horses again (when you load a game, the portraits aren't saved from the previous game if a horse is equipped). The game did crash when I shopped for my son, then clicked to edit his portrait - and the screen went black.
The debug file and autosave is included in the zip.
http://dl.dropbox.com/u/16872572/black%20screen%20.zip
I noticed that you fixed the issue of when a kingdom takes over an empire city that the shard didn't upgrade to a greater shard. Thanks for that! I don't know if this is intended or not, but you can not create a tower of essence in a captured empire city (if kingdom, don't know if empire) when you have a greater shard that is connected.