I swear, I think the old generation models show up under the refurb section, even though they are still new. I bought my 5th gen 30GB iPod right from the refurb store right after the 5.5 update. The thing was spotless, and looked like it had never been out of the box. The same is true of my refurb 1st gen Touch, bought after the intro of the 2nd gen. My Powerbook was similar, but it was actually a CompUSA refurb, not an official Apple refurb. They had just put it out as a display model when the Intel MBP came out. I was a bit nervous when the sales guy said he had a display model, but it was in perfect shape, and was about 1/2 the price.
This might just be my runaway imagination, but it seems like the put the previous gen stuff in the refurb store just to clean them out. But, hey, I like a good conspiracy theory.