Ugh, looking back over this thread I think we're just arguing thanks to my own stubbornness.

Optimisation is of course vitally important once the age gets really large, and texture sizes will need to play into that. When I'm building ages like Llantern, though, I want to use high-res textures to try and make the nicest looking thing possible. If it takes up too much memory, I'll release a lower resolution version of the age.

Sorry for getting worked up about nothing. I'm just getting caught up in my goal of making it look really nice...
I'm actually not sure if Cyan's plugin DOES limit stuff to 1024x1024. I'm inside the texture options with a 4096x1024 texture (it's a skybox, I'm not applying that high res to a rock!) and I can ramp the export to the full size... hmm. Maybe it cuts down the resolution as part of the conversion?

EDIT: Just checked in game. The texture looks hi res to me. The best way to check would be to extract the exported textures, but I've totally forgotten the name of the program I used. :\
EDITx2: Riveal, duh.

I certain that the 1024x1024 limit is bogus.