Gershon Galil has discovered an interesting paper (for mention of which I thank him). You can access it here (and it will automatically download in PDF).
The author writes, in his conclusion:
As a result of the aforementioned data, many archaeologists now believe the domestication of the camel occurred sometime in the 3rd millennium B.C. Scarre states an early domestication date for both species of camel, writing that “both the dromedary (the one-humped camel of Arabia) and the Bactrian camel (the two-humped camel of Central Asia) had been domesticated since before 2000 BC.” Other scholars, such as Saggs, also agree with an early camel domestication date by “proto-Arabs” of the arid regions of the Arabian Peninsula. Macdonald’s research in southeast Arabia has apparently revealed more evidence. According to him, camels were probably first domesticated for milk, hair, leather, and meat, and subsequently travel across previously impassible regions in Arabia as early as the 3rd millennium B.C. For those who adhere to a 12th century B.C. or later theory of domestic camel use in the ancient Near East, a great deal of archaeological and textual evidence must be either ignored or explained away. Bones, hairs, wall paintings, models, inscriptions, seals, documents, statues, and stele from numerous archaeological sites all suggest the camel in use as a domestic animal during the 3rd millennium B.C. in the ancient Near East. The wide geographical and chronological distribution of findings related to camel domestication further strengthen the argument that the camel was domesticated far before the 12th century B.C., and with each new discovery the evidence will likely reinforce this theory.