I want to use "can not" instead of "cannot"

I was proofreading something (because, according to my elevator speech that I should have, "I solve language problems"), and saw that the writer used "can not" instead of "cannot." I wanted to see what language pros say about it, because it seems to me that "can not" is acceptable, which Oxford and Grammar Girl (who's made a total success out of language nerdiness) say as well. 

Writer's Relief goes so far as to say "cannot" should be used, and I find a comment by Gideon Roos interesting: "It follows the grammar tendency set up with do not and should not etc."

Commenter James Gentry mentions a post by Languagehat (whose quote I kept in my blog's "masthead" even though he removed me from his blogroll) about it, in which he says, "The only context in which can not, two words, occurs is as an emphatic alternative: 'You can do it, or you can not do it'.” 

I seem to remember "back in the day" (whenever that was, and if it really should be considered that, which is worth another blog post) that the conventional construction was "can not." I think "cannot" slipped into acceptance to the point where it's a given. 

Even though I'm inclined to use "can not" and probably have, to Languagehat's and other people's dismay, the final word on the subject seems to be from the Associated Press, which issues language proclamations and rules all the time. When I did a search for "cannot" several articles came up. But when I did a search for "can not"...nada. 

So I'll go with the AP, since that's closest to my language world's order. And again, I'm proofing and editing and writing stuff all the time, so I should know better. And don't worry--I ended up correcting that "can not" to be "cannot," so all is well.