There may be alot of us with 35mm rolls of E6 in our freezers. I've bought or traded film and now have a bag full of E6 in the freezer such as Provia, Velvia, Sensia, E200. Some of it is probably 5 years old up to 10/12 living in a standard refrigerator freezer. What's your info on any problems to be encountered.
I just finished a box of velvia that expired in 93. Since the film came out in 1990, it's about as old as you're going to find. No issues as long as it's always stored properly. I have seen color shifts in some old kodak stock but none in E64 which I shot 3 years ago and had expired in the late 80's.
One problem with long term storage of around 5 years in the freezer is embrittlement and sticking of the emulsion — the film may actually tear/snap unexpectedly. It needs as a minimum 24 hours to thaw out. If you have a camera that is manually wound on, load a roll in that and expose every frame with the lens cap on, then rewind it. This will demonstrate whether the film jams or winds on without any problem. In a camera with a motor drive the speed of the drive is what has been known to fracture the emulsion. I have experienced this with films stored for 6 years in deep freeze (Velvia 50 and also E100VS).