I made a simple mod which gives some Heroes VI Dungeon creatures textures from Heroes VII.
To compare- H6 textures:
[url=http://oi59.tinypic.com/2whqv82.jpg]Pic[/url]
Some screens from the mod.
Link to download:
[url=http://www.mediafire.com/download/rc9vfnhvd54nlll/Data22.orc]Download[/url]
Put the file to the game folder.
Edit: If the file Data22.orc already exists, change the number of downloaded file to next(for example Data23.orc).
Some models are different in Hereos VII and textures doesn't fit on all H6 objects. For Example Faceless has changed wings shape. All Heaven creatures have modified models.