I had the same effect on my N900, probably.

Fortunately, I had a defect N900 (with unrepairable SIM-card recognition error) in my drawer, so I could exchange the whole upper half with screen. This seems to be much easier than replacing the housing part (its like replacing the digitizer).

I cant provide you with a good source for buying a replacement. You might have seen this thread http://talk.maemo.org/showthread.php?t=88815 , which sounds like it is more kind of luck catching a good one (eBay or Alibaba and all the Watto's places).

But at least you are not alone with those delamination symptoms.

Cheers from Berlin
Ulle