I posted here earlier that I had missed my citizenship test. I am posting this as an update; hopefully it will help others in my situation.
A quick recap of what happened: I submitted my application in Nov. 2011, received acknowledgement letter in Jan. 2012, case started processing in Feb. 2012, received letter in Nov. 2012 to appear for the test in Dec. 2012. However, I wasn't able to write the test. I called CIC and they said it was okay and I could send a letter to Scarborough and ask them to put my application on hold until I was available again. This is what I did, but then my situation became favorable and I sent another letter to Scarborough and asked them to remove the hold. Scarborough complied to both my requests (I know because of the results of my Privacy Act request). I got another letter from Scarborough in mid Jan. 2013 to appear for a test in late Jan. I wrote the test and in late Feb. got another letter to appear for the oath in early Mar. And now I am a very proud Canadian!
The process worked, but I don't recommend it to anyone; the wait will kill you... .