According to an article at DigiTimes, CMC has begun shipping single-layer 15GB HD DVD-R discs and is planning to produce dual-layer 30GB media in the 3Q of this year.
Already having started production of HD DVD-R discs in May, CMC Magnetics stated it is preparing for volume production of 30GB single-sided dual-layer HD DVD-R discs in the third quarter, according to the company.

The company is already volume shipping single-sided single-layer 15GB HD DVD-R discs, and CMC plans to volume ship the 30GB discs in the third quarter, according to the company.
If you'd like to read more, head on over to DigiTimes.