This post really interested me so I posed a question to my Chartered Accountant and got the following answer thus far (my Chartered Accountant is still researching this to see if this is even legal). With what you are saying, my Chartered Accountant is assuming that 1) Your spouse has permanent residency in Canada; and 2) Your spouse has a social insurance number in Canada, and 3) Your spouse has lived in Canada for 6 months out of the year. Given those 3 points, then yes, you can legally claim your spouse as a dependent if your spouse is not employed. You can't write off your spouse without the 3 points being true because they are neither a resident or citizen of Canada. An Adult must have a social insurance number and be a resident of Canada before you can even consider claiming them as a dependent. Turbo tax may allow you to submit a claim but if CRA asks you for documentation you will have to prove those 3 key points.
So I am curious. Does your spouse have residency already? does your spouse have a social insurance number? and has your spouse lived in Canada for more than 6 months out of the year?