Some of Jerry Goldsmith's lesser known scores might be what you're looking for.
Capricorn One and Outland spring to mind. Outland also had a "in-universe" track for a nightclub sequence. The CD containing both soundtracks may be hard to come by these days though!
James Horner's score to Battle Beyond the Stars is also Star Wars-esque, but Roger Corman recycled it for a half dozen other movies!