Interesting thread, to which I think I can add some news:
Last week, I visited the PCP Roadshow, a mini fair hosted by Nikon, Canon Sony, Kodak and a number of photo accessory manufacturers currently that tours through various German cities. On this show, I visited the Kodak booth and asked their representatives about the poor availability of TMZ 3200. I told them I observed that TMZ 3200 is very hard to get, and if indeed I found some film, it was always close to expiry or already expired albeit only for some months). I got some interesting answers:
1. TMZ 3200 is not being phased out. It seems that Kodak only infrequently manufactures batches of this film and then offers it to their retail channels. It appears that they had trouble buying some of the raw materials needed to produce this film. I was told that they're working on a new batch which should be available later this year.
2. Kodak recommends to use the film within 6 months after purchase and to be very careful about storage conditions. I interpret this in such a way that the film's 'best before ...' period is very short, and that when film is indeed available again I will only stock up for supplies to last for 6 months so that my stock will be depleted before film quality inherently goes down.