Multiple Theme Cascading / Overloading in Magento

Lets say we have a 'default' theme for our Magento (1.4+) Shoe store, we have styled this so that it contains lots of shoe related images etc. We now want to design a limited-edition theme that is very similar to the default theme, just that it replaces some images and changes the structure of a page a bit. This wo开发者_StackOverflowrks well, since we can create default/limited_edition and overload the default theme.

Now we have these two themes working well, we want to create a "limited edition sale" theme, this is exactly the same as the limited edition, but has sale graphics over it - how do we do this? There doesnt seem to be a way to have magento use 3 cascades of themes? Do I really have to duplicate the entire limited-edition theme and change it to include sale graphics?

A good example of what i would like to achieve can be found in the Kohana Framework: "Files that are in directories higher up the include path order take precedence over files of the same name lower down the order, which makes it is possible to overload any file by placing a file with the same name in a "higher" directory" - this supports as many cascades as you need

You're right, 3 cascades is impossible in Magento theming. So you could choose to create new theme by copying previous one and customizing it. One more solution - to create custom blocks, which extends standard ones but with custom selling templates - I think you have not so much places where you want to put new graphics over. After sale is finished switch off the customized blocks and previous design will be back.