> I know for years CDs have had CD-Rom bonus material, but why is it you
> never see CDs with bonus DVD material?

I've had the same thought before, but I believe this is not technically 
possible. The format and media for DVD is a totally different than 
Compact Disc/Enhanced CD. This could be potentially work with 
SACD/DVD-Audio and Video DVDs though. For the most part, bands doing 
this are just including the DVD as a second disc.

Ryan