Hmm different items ???
How many different textures, how many different colors and how many different other items that are customable with textures and colors.
Damn and the intensity of each color can be different, so nearly every cloth part is different from each other cloth part.
Multiply all this numbers and you get a number surely far above the 10k different items.
So my guess will be damn lot different items in 5 years, maybe above 1mio as cryengine should be able to handle it