I have one of those. They work great. I put it in an Atech Fabrication case and it is seemless. The Atech case is made of black anodized aluminium and the Griffin Powermate is available in black as well.
Combined with a VFD display and a few "tweaks" (proper sequence on skins - as the button can act as a "mouse" with clicks and all) on Xlobby it works pretty good.
Check out the case here (this one is silver):
http://www.atechfabrication.com/products/atech_3000.htm
They are VERY expensive though (the cases not the button)