Almost even more idiotic, but it worked in my case (game instruction pages):
Render the text as textures. You only need black/white, so you can cram up to 4 “pages” of text in a single texture. Then create the appropriate masked materials…
The textures itself dont need to be that big in resolution and they compress fairly well, so not too much trouble there…
The only drawback is that editing text on-the-fly is not so easy anymore…