I am a Canadian citizen with a TN visa, married to a Canadian citizen with a green card, residing in the U.S. What would be the best way to adjust my status to permanent residency as well? Can I apply for a family -preference 2a- green card while holding the TN visa? Since the petition would likely take longer than 1 year, would it still be possible to renew the TN visa?

As the spouse of green card holder, you would be in the 2a family-based immigration category. You are already aware that, if you applied, you would be in the visa backlog for more than one year. TN status is issued for only 1 year at a time.

There is no recognition of dual intent for the TN category. This becomes an issue when you are applying for re-entry or applying for a renewal of your TN status. If the INS discovers that you are the beneficiary of a pending immigrant petition when you apply for your TN renewal or when you seek re-entry to the United States, you may be refused on that basis.

If your husband filed a 2a petition on your behalf, you would require at least two TN renewals before your visa priority date was reached. I also assume that you would have to occasionally travel outside the U.S. during this time.

You should not make any misrepresentations to the INS, although you are not obliged to offer unsolicited information either. If some care is taken, the issue of whether or not you are the beneficiary of a pending immigrant petition will not come up . If you have some concerns, you may want to consider switching to the H-1B category which does permit dual intent.