Mine has the crack too, it is only a hairline one right now.
I already posted this question at maxconsole, but I thought id ask it here also because it may have something to do with the crack in question:
Is the DS Lite hinge designed to open at a full 180 degrees? If you open your DSL normally, it will click into place at 170 degrees, but if you pull it back a little more, it will click into place at 180 with very little force.
I am wondering if opening it at a full 180 will put more stress on the hinge, possibly causing the crack?
BTW, one of the guys at maxconsole already called Nintendo about this problem. They told them that there would be a $50 fee to fix this crack. Nintendo obviously does not recognize this as something that is caused by a defect.