I'm considering getting an iPad Pro just for this purpose. With a 13" screen, you can fit an entire 8.5" x 11" page on the screen at 1:1 scaling. Alternatively

I'm considering getting an iPad Pro just for this purpose. With a 13" screen, you can fit an entire 8.5" x 11" page on the screen at 1:1 scaling. Alternatively, there are some really interesting 13" epaper tablets coming out soon that might fit the role more aptly.