After half a century's absence of verifiable evidence, there is now a flurry of confirmed ocelots sightings in Arizona! In just over a year period 3 ocelots have surfaced - one road killed near Globe, one camera trap photo from Cochise County, and the last one in Feb. 2011 treed by dogs in the Huachuca Mountains. This latest image, in my opinion, appears to be an older individual and has probably been around for a while.
Perhaps there has been slow recovery of parts of the Sky Island region from better management and the cats have returned. The region was in bad shape in the late 1800's and through the early 1900's. Logging and cattle ranching had decimated wildlife habitat and hunters and trappers killed off most medium and large animals, especially predators like ocelots.
Perhaps global climate change has caused ocelots to move northward as javelina, coati-mundi, and other neo-tropical species have done, although historical records indicate their historical existence in the region.