Hustler has 2. The first one did so well for them that it spawned a sequel. It made a huge deal because actor Evan Stone cut his hair after years of refusing to do so to play Kirk.
Hustler caught a bunch of crap for sticking mainly to the parody market but as successful they've been its spawned a ton. Vivid did the Batman one and spent a crazy amount of money on it and now Hustler is saying that Avatar will have the highest production cost they've ever done with the company looking to include a 3-D version of this as well....
To show what else Hustler is doing along with this:
This Ain’t CSI XXX: Chatsworth
This Ain’t Curb Your Enthusiasm XXX
This Ain’t Glee XXX
This Ain’t I Dream of Jeannie XXX
This Ain’t The Cable News XXX
This Ain’t The Soup XXX
This Ain’t The Hills XXX
To show you how extensive this recent trend in Porn has become there is already:
Not The Cosby Show XXX
Not Three's Company XXX
30 Rock A XXX Parody
70s Show A XXX Parody
Big Bang Theory A XXX Parody
Cheers A XXX Parody
Not The Bradys XXX (which has garnered 4 sequels including a Partridge Family cross over)
The Office A XXX Parody
Scrubs A XXX Parody
Seinfeld A XXX Parody
This Ain't Beverly Hills 90210
This Ain't Charmed
This Ain't Celebrity Fit Camp
This Ain't CSI: Miami
This Ain't CSI
This Ain't Dancing with the Stars
This Ain't Gilligan's Island
This Ain't Happy Days
This Ain't The Munsters
This Ain't The Partridge Family
This Isn't Big Love
This Isn't Twilight the XXX Parody
This Isn't New Moon the XXX Parody
Tru a XXX Parody (Tru Blood)
Whos the Boss a XXX Parody
WKRP in Cincinnati a XXX Parody
The company doing it usually indicates the titles with Hustler's being the "Ain't" tag. According to sites like DVD Empire there are currently over 200 of these parodies including the really bad ones that have been produced for years.