(Atmel has just implemented a new Sampling Scheme, BTW. Traditionally, it was supposed to be difficult to get Samples of Atmel chips.)
Note that if you're a "real company" of the sort likely to use tens of thousands to millions of chips, a sample request is likely to be answered with an offer to send around a sales team, engineers to assist you with your design, development tools, and more. Which goes back to what I said about samples being cheap marketing. Even the 5 minute phone call is likely to cost the company more than the sample chips themselves (and I suspect that the infrastructure to support sampling for the customers that really "deserve" it cost more than product they send out. (applies to the sort of avr-class chips I assume we're mostly talking about. If you start phoning places up "I'm working on a new guided missile system for the army, and I'd like to get a sample of your $300 mil-spec 9dof inertial navigation chip...", you've probably crossed a line.)