Beyond what is listed here: http://maru-chang.com/hard/scph/index.php/english
I haven't been able to find out how many possible variations exist out there. It would seem in the US the main releases were the black, red, and blue. Scouring eBay I've found bright pink, silver, orange and what I assume is emerald from sellers in the UK. Beyond that I've found nothing. Knowing Sony I would imagine they had limited releases of some colors to match the LE console releases but I've never seen them pop up anywhere.
Mainly looking to flesh out a collection as I've got a thing for memory cards.