But I'm thinking less Vance and more Beowulf,
There is a setting supplement for Pendragon that is specifically Beowulf era Norse:
Land of Giants.
A few references to Sinbad -
Arabian Sea Tales (Better Games),
Mazes and Minotaurs (Ollie LeGrand). M&M is free in PDF, and a genuinely old-school feel, not quite D&D knockoff. Heavily Greek themed.
I've heard there's an RPG based directly on old Hong Kong Kungfu movies.
Several, actually. The two that come to mind are
Hong Kong Action Theater (White Wolf) and
Feng Shui (and its second ed,
Feng Shui 2). I've got FS & FS2, and have run FS2. I don't find it hard to run, but I do find it hard to write adventures for. I've never read HKAT.
Hero System's supplement
Ninja Hero is broader in scope, covering a wider range of Martial Arts themes, especially martial-arts focused manga and American style martial arts based supers.
Palladium's
Ninjas & Superspies is also wider than the HK subset, but it's one of the few genres that actually works really well in Palladium's system.
There's also a parody game - the original (out of print)
Ninja Burger (9th Level) - think HKAT style ninja doing infiltration to make burgers appear on people's flat surfaces - unseen delivery.
Space: 1889 has nothing to do with the Burroughs John Carter (A Princess of Mars, etc.) stories, does it? I've never heard of any connection there.
The flying ships, the 3 kinds of martians, and a number of other thematic elements...
Unlike Verne, Wells, and Doyle, Borroughs was still under copyright protection in 1987, and so isn't mentioned on the cover, but the DNA of it is definitely included.
The most important being liftwood - which creates the titular Sky Galleons of Mars of the companion boardgame.
The thing about 1889 is that it's not a direct lift from any one of the major authors it pulls from (Verne, Wells, Doyle, Borroughs) but is an admixture. You can't have Carter & Thoris' empire if the Europeans have flown there... but you can have 2 kinds of urban Martians and a type of wild martian... sure, they fly instead of run...
Not to mention that Frank mentioned it in some online discussions in the 90's