Since you can't buy a house, or at least I don't think you can, where can I safely store my inventory (books and cool artifacts) without risking them disappearing on me. Currently I am storing my books in Cosades house but if i go a certain number of days, will they disappear?

Unlike in Skyrim, there is no area respawn and almost no container respawn so you can leave stuff anywhere. Caius's house is fine as are the mages guild rooms. You could even leave stuff on the ground outside, nothing will happen to it.

Awesome.