Arduino Due Mini/Nano

I wonder if the 'vanilla version' of the SAM3X8E can be used to make own Arduino-compatible boards, since the Due page says:

The bootloader is preburned in factory from Atmel and is stored in a dedicated ROM memory.

Would this mean Atmel ships a custom Arduino bootloader with these chips, or does the Due use a standard Atmel bootloader? If the former, will be able to burn a bootloader ourselves? :~