Zeppelin vs. Pterodactyls would have been a Land that Time Forgot/Mysterious Island type film (with maybe some DC Comics War That Time Forgot mixed in ?). A German Zeppelin during WWI is blown off course and ends up in a lost valley where dinosaurs still exist. Looks like a pretty cool idea, but Hammer had grown tired of the stop motion process after When Dinosaurs Ruled the Earth (1970) and this never progressed beyond the poster stage (as did most of these).
Some great Tom Chantrell poster art (as are all these except for Vampirella), this would have starred Caroline Munro (and would have an instant classic if they kept that costume design).
Set in 1870's India (complete with Bengal Lancers), this would have been an attempt such as 1974's The Legend of the Golden Vampires to inject some life into the Dracula series by moving it to an exotic locale.
Raquel Welch as a female pirate in a period swashbuckler movie !! - Sign me up ! (The mind boggles at the thought of what would have been).
What would have been a Hammer version of Henri-Georges Clouzot’s classic The Wages of Fear (1953) - with probably more scantily clad females then the original (which had none).
What was a proposed 197(?) production starring Peter Cushing that was most likely inspired by the rash of nazisploitation films post The Night Porter (1974) & Ilsa She Wolf of the SS (1975).
Hammer's attempt to film another Dennis Wheatley after the well recd. The Devil Rides Out (1968).
By the mid 70's Hammer was in serious trouble as their gothic horror was rapidly following out of fashion with movie going audiences. Efforts like Dracula A.D 1972 to update their product had meet with luke warm reception and the company proposed "Nessie" project (a Loch Ness monster movie) had turned into a huge money pit. Michael Carreras put in an ad in Famous Monsters asking readers what film Hammer should do next and the overwhelming response was Warren's own Vampirella. A script outline was done by Jimmy Sangster and Carreras attempted to put together financing. Caroline Munro was originally offered the part and allegedly some test photos & footage were done of her, but she balked after reading the script and discovering there was major amounts of nudity involved (Valerie Leon would turn down the part for the same reason).
Hammer then offered the part to actress Barbara Leigh. A tall statuesque brunette, who had co-starred with then current boyfriend Steve McQueen in Sam Peckinpah's Junior Bonner from 1972. She certainly looked the part (and looked great in that costume) and Hammer signed her to a six picture deal. In 1975 she appeared along with co-star Peter Cushing at The Famous Monsters Convention in N.Y.C. to promote the upcoming film and was featured on the cover of a couple issues of Vampirella. Things seemed to going well.
But, alas it was not to be. Hammer couldn't come up with the financing (a deal with A.I.P fell thru when they insisted on a big American name to co-star). Plus, things got a bit ugly with Jim Warren as there was disagreements about the merchandising side (among other things) and the project imploded - along with Hammers future & Barbara's film career.