Mmm, I don't think so. You can be subcontracted from one company to another under TN-1, e.g. if you are employed by a temp agency for example and they contract you out, but you cannot be self-employed and the relationship between you and the subcontracting company must be arm's length, i.e. you cannot have a controlling interest in the company that is paying you. That is self-employed and the CBP manual says in that situation you should get an E visa.
The problem is that the job offer letter has your name on it but the payment isn't actually going to you, it's going to your company and you control that company, so you are effectively self-employed.
I think you might want to seek legal advice on this one but this is what it says in the manual:
Self-employment also clearly conflicts with the intent of the NAFTA Implementation Act and its accompanying Statement of Administrative Action, which states, at page 178, “Section D of
Annex 1603 does not authorize a professional to establish a business or practice in the U.S. in which the professional will be self-employed.” In this regard, Section B of Annex 1603, which deals with “traders and investors,” establishes the appropriate category of temporary entry for a citizen of a Party country seeking to develop and direct investment operations in another Party country. Canadian or Mexican citizens seeking to engage in self-employment in trade or investment activities in the U.S., therefore, must seek classification under section 101(a)(15)(E) of the INA.
Although the issue of self-employment was never specifically addressed under the regulations promulgated by the INS pursuant to the CFTA Implementation Act, the bar on establishment of a business or practice in which the professional will be self-employed is consistent with the intent of the U.S. and Canada in entering into the CFTA. Since entry into NAFTA was not intended to substantively change the treatment of professionals, this explicit bar merely clarifies existing law.
Note that the bar on establishment of a business or practice in which the Canadian or Mexican citizen will be self-employed is in no way intended to preclude a Canadian or Mexican citizen who is self-employed abroad from seeking entry to the U.S. pursuant to a pre-arranged agreement with an enterprise owned by a person or entity other than him/herself located in the U.S. On the other hand, a Canadian or Mexican citizen is precluded from entering this country in TN classification for the purpose of rendering pre-arranged services for a U.S. corporation or entity of which he or she is the sole or controlling shareholder or owner or over which he or she holds de facto control.
What this last paragraph appears to be saying is that if you were self-employed in Canada you could still be directly employed by a TN-1 sponsor in the US, but you can't get around it by using a Canadian corporation, because the corporation would have to register for an EIN in the US to do a US payroll, so at that point you're in the same situation as doing it via a US corporation.
Steve.