Well, I found a print head on Ebay that was just under my "fuck it just get a new printer" line (that line was 50 bucks by the way), and which included a screen shot of a printer nozzle test that proved it didn't have my problem. Simultaneously, Canon emailed me back (in the middle of the night on a Saturday no less) and said, "yeah, you'll need to take the unit in for service".

So we'll see how the new print head goes. :-)