i'm thinking that you might want to have 2 dvd burners in your computer? correct me if i'm wrong. if you computer is good enough you can burn 2 dvd's at the same time. or instead of storing the data onto the hdd when you burn a dvd, it can read from the first drive and then directly write on the dvd in the second rom.
can you post the specs of you computer?
MacBook 2.2GHz Santa Rosa | 120GB HDD | 4GB ram
Intel C2D E6300 @ 3.2GHz | 4GB ram | 880GB total HDD space | Gigabyte P965-DS3 | eVGA 8800GTS 640mb | Corsair HX 520 | Audigy 2 ZS platnium | Antec 900