[cflsystems]

Actually I believe the skin you are talking about was originally done by someone else and not QT. Also not sure why this is such a problem - just modify CSS and template to not reference the sprite image but your own. There is no need to modify the sprite image at all. Not that difficult to do.
About making logo replace as easy as upload an image in admin - that won't work. It will be extremely difficult if possible at all to account for all possible designs, layouts, logo sizes, etc.