MagicTouch offers DIY IR touchscreen kits using their modular OPTIR technology. This allows you to integrate the IR array in your existing bezel with a spacer to offset from the LCD screen.
Optir Touch Overview
http://www.magictouch.com/IR_screen.html
Example 65" Kit
http://www.magictouch.com/setup-082707-65.pdf
Demo Video
http://www.magictouch.com/ASF_0164.ASF
The downside is that it is
EXPENSIVE! I ran their Excel sheet and the total cost with controller was
$782!
Oh well, it was worth a try...