Ch. namaquensis are hard to come by. I believe that a few people in Europe work with them, and Ron Tremper had brought some in from Namibia several years ago. The thing is you can apply for a game license to get them, but you have to go field collect them yourself.
As far as their care requirements are concerned. In my personal opinion the best chance with them would be to keep them like the gecko species Palmetogecko, which are from the same region. You'd need a large screen cage, with a container attached at the bottem to hold sand, some branches, maybe some succulants(I would conjecture that Jade plants;i.e. Crassula would work wonderfully, especially when it got bigger) Very high temps during the day, with no humidity, and at night have a fogger set to run for an hour or two, to simulate the natural fog that comes in off of the ocean. They also would need a varied diet, you would want to mix in some small lizards, small snakes, scorpions. In their natural habitat they eat the small viper(B. perengyui?) and scorpions. I hope one day to attmept to work with them, because outside of the big 4 chams(Parsonii, Oustaleti, Verrucosus, and Melleri)these are my favorite. They look like they have so much character and mean.LOL I hope that helps out. I've been trying to read as much about them as possible. The adcham site is good, and there is an article in Reptiles mag. from like 1998-99 that deals with reptiles of Namibia and they are featured prominantly in it. I think the author is either Ron Tremper or Karl Switak.