Source : http://www.durolitum.co.uk/gladtypes.html# According to this some of those guys won't be made because not historically accurate. Anyway, I will do anything (armor weapons, props...) for them. Tell me what you think I hope you will like it
I'm not really confident with that importing part. I'll try when i have time but i don't really know how to do it, also my collada plugin is a bit older compaired to the game, may have to switch to blender to get them in the game.
Maybe you could make an other type of obstruction. One that prevents user from building but not units from walking. This way you would also get a starting point for units on walls.