Whoaw...That's a great idea...Even if it's not every month having a mini-poster of one of the dungeon/dragon artist with a short interview (What they are working on, preliminary sketches, rejected concepts for covers and so on...) would be great.
I'd love to be able to download the maps in multiple section that I could handle to my players without any text or hints about secret passages, traps or special items.
I also support the idea of having the new monsters and main NPC in a similar layout as the monster manuals.
I would also welcome web enhancement like 'Tunarath' or other stuff that you left out because of space restrictions.
And if for any reasons you want to restrict access to these to the dungeon masters you could password protect them and put the password within the printed issue...
