The Red Steel setting for 2E D&D featured similar elements in the campaign, so if you're able to find the two boxed sets (Red Steel and the Savage Baronies) they could prove to be an invaluable resource for that type of campaign.
IIRC, it featured all the standard 2E races, as well as three new ones: The Lupins, the Tortles, and the Rakshasa (no relation to the demon Rakshasa; they may have been called the Aslan, but I think that was Traveller). Anyway, it was a splinter setting of Mystara, set on the Savage Coast, and featured Cowboys, Samurai (especially the Rakshasa/Aslan), and Barbarians (mainly the Goblinoids). IJR that there was a fourth race: the Aranea, a sorta spider/human hybrid that lived in the jungles of the Savage Coast. Also, the Tortles tended to be monks, and as the setting was along a coast, you also had pirates.
Cowboys, Samurai, Barbarians, Ninja/Monks, and Pirates. What's not to love?