as far as desert specific items when I trek out into the desert. There are only a couple things I take that I normally dont carry in my camelback.
1) a 6x8 plastic tarp I can use for shelter, such as a trench shelter.
2) I carry extra plastic bags for water procurement.. such as solar stills and vegitation/transpiration bags.
3) obviously a container of sun block and a good bush hat or floppy hat.
4) and I always try to wear some sort of long sleeve shirt. in my pack I always carry a insulated gortex jacket or slip over.
5) a good snake bite kit
I would be interested in hearing what desert specific items you carry aside from the essential "anywhere" survival items
Jimmy