Howling 3, 5, and 6 Coming to Blu-ray
http://www.horror-movies.ca/horror_18868.html
Myabe it's not quite The Howling trilogy you had in mind but I'm sure your chopping at the bit to get your hands on Howling III: The Marsupials, Howling V: the Rebirth and Howling VI: the Freaks all in High-Definition!share
As of yet no specifications and supplements have been announced but as all three films are housed on one single disc, so I'm guessing that's the lot.
The suggested selling price for Blu-ray is $16.98 and is heading for a October 19th release.