If you got to the 8900 page on cnn.cn they have the black trackball. Not only do they have the trackball but they also have a video showing the removal, installation and use of the trackball in a curve. There is a not however that states "you lose the glowing effect of the trackball in the older phones."
BlackBerry Curve 8900 OEM trackball- Sony, Acer, Accessories Store, Dopod/O2, Alcatel, NEC, 3G, Samsung, LG, Tools, P
I am totally going to do the whole stealth look now with the black trackball. I won't miss the glowing I know right where that ball is! Oh and cnn.cn has 15% off until 12/27/08 if you use code "holiday15"!