I know this is quite an old post, but was searching for the same type and came across an eBay seller that carries these along with eBrake and Arm rest gaiters.
Just thought I would share.
http://stores.ebay.com/TOP-GAITERS-BOOTS/PORSCHE-/_i.html?_nkw=boxster&submit=Search&_fsub=1114847016&_sid=668506186