High Desert Seed and Gardens (Montrose, CO) provides a nice selection of open-pollinated vegetable, flower, herb, and grain seeds adapted for high-altitude desert gardens. 

J and L Gardens (Española) sells at local farmers markets and offers over 500 varieties of heirloom and open-pollinated vegetable seeds. 

Native Seed/Search (Tucson, AZ) is a nonprofit seed conservation organization that preserves and sells many arid-adapted vegetable, grain, and flower seeds, many of which originated in what is now New Mexico. 

Painted Desert Seed Company (Sanders, AZ) provides open-pollinated seeds adapted to high-elevation desert gardens. 

Plants of the Southwest (Albuquerque and Santa Fe) is a great resource for native grass, wild flower, and open-pollinated vegetable seed. 

Seeds Trust (Littleton, CO) is a thirty-year-old seed company offering an extensive catalogue of open-pollinated, heirloom, and organic seeds grown in and adapted to the high-desert West. 

Space Dog Farms (Albuquerque) is a young company selling a range of vegetable, flower, and desert plant seeds grown in New Mexico.