Wbdisco, I would not seek refuge from the force of federal law in a contrary state law. The specific example you use has been addressed in Gonzales v. Raich. The reasoning in that case is that even where the marijuana is not in commerce and where it is not part of an interstate transaction, it still is part of a matter that is in interstate commerce and so is subject to federal control.
I very much prefer the dissent of Clarence Thomas in that case. He noted that "interstate" means between states and "commerce" indicates buying and selling, and that where there is no interstate transaction and no commerce, federal authority cannot stand on the interstate commerce clause.
I admire the clarity of his opinion, but recognize that it was a dissent. He lost.