[bazzargh]

The word 'holidize' seems to have been in use by marketroids for a while, see eg: http://design.inkzoo.com/how-to-holidize-your-logo-design-to...

...and you'll see from the examples there that it's not just Christmas - Halloween, Thanksgiving, whatever. In my day job I see this done a lot for product sales, there are logos/backgrounds queued up for some holiday or other most of the year.