Old West is a fan-made variant setting of Hollow Earth Expedition using the Ubiquity system. The setting and a few adventures are all available for free at the Mythic Eras website. All of this fine work is written by Ingo Kvalø-Hamann.
The Wild West. This is a variant setting for the Hollow Earth Expedition RPG. There are a small amount of Mythical elements, but mainly keeping in the traditions of the Wild West or actual folklore rather than Weird West.