Double layer DVD burner for Dell and HP

Taiwanese producers have received orders from Dell and HP for double layers DVD burner. Those orders have to be delivered from next month.
But Pioneer seems to be late regarding the double layer DVD-R. Apple might have to make a choice, either continue to support DVD-R, and wait extra month before being able to equip PM, iMac and PB with DL DVD burners, or "switch" and propose DL DVD+R burner as a BTO...