Well guys the new AS3 flash cart system can have skins hot swapped in and out with out having to recompile the actionscript code.
You can even have multiple skins on the same cart and use different ones in different places of your website.
This is all because the flash cart system itself runs seperate from the graphical user interface that the customer visits.
When you purchase a new cart skin, or if you edit your own custom skin, you can place the swf file for it in the "skins" directory of your flash cart installation directory. Then in the config file where you "embed" the cart on your website you include the name of the skin you'd like to use (the skin MUST be available in your skins directory).
The other plus to using the skin system is you can keep the cart application seperate from your site. No longer do you have to have all that ugly php code and cramped swf files floating along side your website html files. No instead you create an install directory then simply embed the cart from where ever it is. The only litigation is that the cart must exist on the same server as the website you are showing it publicly on.