Hustler XXX 1-26 were filmed by Pierre Woodman when he was lured to Hustler by Larry Flynt. He has since returned to Private where he belongs.
Hustler XXX 27 was filmed by Dan Silver who doesn't have the skill (few directors do) that Pierre has and the lineup of ladies was American rather than Euro.
It's probably the end of the line for tht series and even if they filmed more using the title, it wouldn't be the same.

[Link]