Feshea Desert (placeholder name, I can't remember the name I wanted instead to use) is an area east of Amythist Town. It always has a sandstorm raging through it and you'll will need the Go-Goggles to traverse through the desert. There is an oasis, and a sunken ruins similar to the Ruins of Alph, but that's not immediately accessible. Aside from Trapinch, the Pokemon available in the desert are Tuttby (Psychic type, a sphinx kitty Pokemon) and Coyoco (Fire type, a feisty coyote Pokemon).
http://pixelmonmod.com/forum/viewtopic.php?f=9&t=2918 - My PKMN Rom Hack Project Thread