I think Windows BSOD including QR code was pretty clever idea, although unfortunately it's halfbaked in that it's just a fixed generic URL instead of something specific to the error.
Or even better, a small library which'd allow bootloader to generate it on the fly.
http://fukuchi.org/works/qrencode/index.html.en
That said, with iPhone cameras supporting live OCR and URL detection, a QR code would be unnecessary.