I know the rule. I know the "never submit before it's finished" rule. But I did. I heard a not-to-be-named agent requesting manuscripts that were exactly like mine. So I queried. And I waited and wrote. Waited and wrote. Waited and didn't write for awhile. Then I heard back. It was a rejection, but an awesome one. Agent X stated that she hadn't forgotten and she was sorry it took so long but that she was strongly considering representing me for several weeks but unfortunately a project she was working on was dominating her time.
The letter was LONG and PERSONAL. Both great in the query world.
I don't think anyone has ever been so happy about a rejection letter. And so I'm working on finishing the darn thing and am confident that when the time is right, I'll be able to find representation.