It doesn't matter, whether they have "certified" drivers or not... you buy hardware, and it doesn't work, Apple takes the reputation hit... Joe Schmoe doesn't care if the driver was certified or not, he doesn't likely even know his $5 network card is to blame.. he just know his computer crashes...
Don't get me wrong, I'd love to see UNIX on the desktop with a nice reliable GUI vs Windows... but I can also understand apples reluctance to it..
Well, they could start out with putting it on "New" systems(Dell, IBM, Gateway, HP) that have drivers for all the hardware. Then after awhile new componets that are sold could be labled "apple PC compatible" like on Motherboards, Video cards, Nic cards etc.