Hitachi Maxell has announced that their CPRM compatible 8x DVD-R DL media will be available in Japan on June 8th. Here's part of their press release, translated from Japanese:

Will Hitachi Maxell, Ltd.'s (The execution post president: Yoshito Kakuta)*1 sale of the DVD-R DL(DUAL LAYER) disk for recording for eight-X speed standard record that can be recorded for long time of 215 minutes in the world on June 8 for the first time. It corresponds to copyright technology CPRM protection, and "It is possible to record only once" digital broadcasting program * can record two.

A further making to a large capacity is needed to record the DVD disk in the main current of present wholly by a standard image quality of the program that exceeds 120 minutes like the soccer program etc. though ..standard.. 120 minutes can be recorded. Moreover, a high-speed record to shorten the record time to the record of mass data is requested. The principle and "It is possible to record only once" copy control signal have been added to digital broadcasting though the environment that can receive digital broadcasting is in order on the other hand. The DVD disk corresponding to copyright technology CPRM(Content Protection for Recordable Media) protection and the DVD video recorder corresponding to the disk are necessary to record these programs on the DVD disk.
According to AV Watch, Maxell's 8x DVD-R DL media is expected to cost about 1300 Yen. More information can be found here. AV Watch.