Desert Camouflage with "remain motionless" works. Either wording is fine, really.
I can go for the +4 racial Hide bonus in desert environments, but I'm not seeing much cause to add anything else from the original monster text. Sound ok to you?
Well we still need to do the Sand-Shifters from the original monster text, but I was reckoning on them being a subentry like Stone Giant Elders are a subentry of Stone Giant.
Updating the Desert Giant Working Draft.
Warm deserts sound ok for the environment?
I prefer "Any desert" since there's no mention of temperature ANYWHERE in the original entries. Even Al-Qadim could have cold and temperate deserts in areas with a high enough altitude.