Have you tried approaching Hasbro as a potential game developer for them?

Too bad we may never see this in stores, but I understand your concerns. Designing the other components of the game could be a bit of a pain as well.
Love the map btw! I would suggest to anyone who prints this off to play with that you use Risk Europe pieces with it (if you have Risk Europe). Not only does this version of Risk have a medieval, Narnia-ish theme and look, it's also designed for a map with fewer countries and sea routes, so it may be a good idea to implement at least some of this version's rules while making up your own. (One of the armies available looks a bit like the Calormenes, as well! )
The gameplay is a bit different than regular Risk, though, and the combat system seems to more resemble Axis and Allies than anything else. It also has siege engines (good for the Telmarine army in case you're reenacting certain events in Narnian history ) which do increased damage.
And it even has CASTLES!
So yeah, this version of Risk would probably best blend with what you've created, Geekicheep.

Hey, thanks for the great ideas!

Coracle: no, I haven't approached Hasbro, but I love the thought! If I had contacts at Hasbro I would definitely do that. I'm sure they have a whole team of developers, but man would I love to be involved in a project like that!

Cleander: it wouldn't be a pain (it's not work when it's fun), but it would be a big project that would be more likely to get me into trouble than anything else. But thanks for sharing that tip about Risk Europe! I've never played it, but it sounds like a great game, and might be the best version of Risk to adapt for the world of Narnia. ESPECIALLY if it has castles!

Interesting idea! If I were to make a Risk board based on the Chronicles of Narnia, I'd adapt the original games' method of weighting certain land masses more heavily than others in terms of how many extra armies one gets per turn for controlling them. I'm thinking that Narnia and Calormen would be the ones worth the most to control, Narnia because of its enchanted nature and how much the people of the other lands desire to control it (and because Narnia is the best!) and Calormen because it's described as the most populated and a large country with military might. Telmar would be next, followed by Archenland, with the Lone Islands and eastern islands being their own region but with the fewest points attached. That way someone could try the strategy that Eddie Izzard describes in his famous stand-up bit mentioning Risk: "Put everyone on Papua New Guinea and just build it up," instead putting everyone on the Lone Islands or Ramandu's island and slowly building up to take over the huge countries to the west.