You can buy a replacement case from E-bay for around $18.00 and replace it yourself, here is a link to show how to do it.
http://forum.xda-developers.com/showthread.php?t=407323
Might be better than all the Hassle, if you have a custom Rom. or something else you don't want to load again . I've had my 6900 for
1 1/2 yrs, had the case completely off, painted it black and back together with no problems or no cracks
Tonyk