Here in Atlanta, no Best Buy stores will be carrying the 5D3 in the store, you have to order it. This was learned and verified with a visit to a store that carries the 5D2 and looking at the inventory readout on the BB computer system and looking at the inventory control codes.
I walked into a Best Buy on Sunday, March 25, with a 10% off coupon and a $50 rewards card. Ordered the camera, the 10% off was honored as it did not exclude Canon DSLR (it did exclude Nikon and Sony), applied the rewards card and was all done for $3165 including tax. There were 63 in the warehouse at the time. Now, there are none.
BB called 2 days later and I picked up the camera on Wednesday March 28.