Courtesy of Slashdot, here's a link to a story (in german, so hop over to Babelfish) about hackers upgrading their NEC DVD burners to Dual-Layer capability with hacked firmware.
Story
This is for NEC 2100A and 2500A burners, and 'turns them into' the 2510A. Sounds dubious, and you better wrap that rascal, but if you're feeling brave here's a link to the hacked firmware:
Firmware
Better yet, here's a link to the Slashdot story, so you can read about *other* people blowing up their drives before you try it yourselves.
Slashdot Article
I wouldn't hold my breath for this to work, but someone's gonna be more brave than I am.