I've found some banners to decorate my house with, but I hate the way it moves around in the non-existent breeze. None of the static banners are big enough or are in tatters, so is there any way to disable the animations on the banners located under 'movable static'?

I think you'd have to mess with the nifs and cut off the relevant data. Are you sure you can't use the least moving variant? They range from violently blowing in the wind to very very gently swaying. Is that still too much?