[dustin]

Is ebay one of those companies? http://www.ebay.com/new

Or are they maybe close but not close enough to call out considering the size of their legal department?

To be honest, not being much of a designer, I've seen this scrolling with background switching 'style' become popular on a few sites recently.

I have no reason to doubt that OP developed it from scratch and clearly some of the linked sites blatantly ripped off the entire design, but the question of where inspiration ends and what constitutes 'independently developed' gets murky really quickly.