I nominate Sonny and Jed! Susan George plays the female lead and she's quite good in it. Okay, so she's not really playing a strong woman, but it's a good role, she's the star of the film just as much as Milian is. She plays a low-life outlaw wannabe who falls hopelessly in love with the misogynistic and abusive Jed. A thoroughly un-pc western with strong comedic elements (but I wouldn't call it a comedy western), the ending is simply fantastic. A great film and a great role for George.
Also do check out Norma Bengell's two SW ; The Hellbenders and Phaedra West. She plays two very strong-willed - and very different - female leads, the films are very good and Bengell is one of the best female actress to ever work in the SW genre, too bad she gave us only two performance in the genre.