Many people have expected the adult film industry to be the deciding factor in the battle between Blu-ray and HD DVD. With no clear winner, film makers in the US have decided to be release titles in both formats.
In view of the stalemate between HD DVD and Blu-ray Disc (BD), producers of adult films in the US will adopt both for the time being by offering HD DVD and BD movie titles, according to sources in Taiwan's optical disc drive (ODD) industry.

US-based Vivid Entertainment, one of the world's largest producers of pornographic movies, plans to release HD DVD and BD movie discs early next year, the sources pointed out. Since the estimated average production cost of US$50,000 for a BD adult movie is much higher than that of US$10,000 for a DVD version and with BD players costing between US$700-1,000, the market acceptance of BD or HD DVD titles is questionable, the sources indicated.
I can't imagine there is a huge demand for high-def porn, but you never know. If you'd like to read more, the entire article can be found here.