Hi! I'm going through SVO a lot, and can tell you that there are caviar vending machines at this airport. On the way from the Aeroexpress to Terminal D. I've seen one or two in the duty free section, but as I'm always rushing through this area, I don't remember exactly where.
Anyways, it's better to go on a recon trip if you've got a little time, because Sheremetyevo feels like it's never the same, shops are closing and opening at a mad rate.