Trust me on this: Making just one *good* single player map takes a long, long time. Maybe I'm just a perfectionist, but after publishing 4 single player maps, I can say that even the simplest, "The bre'Unor Attack," took nearly 2 months. The others required the help of over a dozen people and they took even longer. Try to scale it back to under 4 levels if you ever hope to release it before no-one cares anymore.
By good, I mean like a colormap rivaling Bungie's best, 300-action map scripts, and *extensive* testing. You don't know how long it takes to work out all the bugs you'll find. I have played my CoD maps over a hundred times apiece - no exaggeration.
Making it smaller and less elaborate will also make the storyline less official and serious, which is a good thing. CoD talks about things that have already happened and are heavily supported, so thats different. Making stuff up is fine, but don't be serious about it!
-Ares
