Hi Nancy
I think there are two questions left unanswered on this thread - R16 and NAS.
The R16 model was introduced while Mobotix were still struggling to get satisfactory results in testing with SD, so they released a variant of the cameras with built-in CF memory, of which there is 16Gb. The SD models were released later, and the R16 has remained in the range, just not very popular!
As for NAS, Mobotix recommend Overland Storage, and have built-in cross compatabilties with auto detect etc.
(I used to sell Mobotix for 4 years before joining Grandstream)