yes it is possible to do consular processing instead of AOS. Simply indicate that you want CP on your I-140 when you submit it to USCIS.
The advantage of indicating CP on the I-140 is that if your I-140 is not approved, you will never have indicated immigrant intent (AOS) and thus will be free to continue renewing your TN. If instead you filed AOS, then the instant that you file AOS you will be unable to renew the TN and unable to re-enter the US on a TN without an advanced parole document.
The approach I used was to file I-140 indicating CP. When I-140 was approved, i went to the border and got a new TN with 365 days till expiry. There were some questions from the border guards about having a TN and an approved I-140, but ultimately then had to let me in as i had never indicated immigrant intent (filed AOS). By the very nature of having to do CP, i had to leave the US so my stay in the US was necessarily temporary.
After I had entered into the US, i decided to file AOS within a few weeks along with AP & EAD. This meant that I had to remain in the US for a max of 90 days until AP & EAD were approved as i had now indicated immigrant intent. This was not an issue because I had a new TN with 365 days to expiry. I got my GC about 40 days later. it was a very smooth process.