I am familiar with a claim by Rawle, but I don't know of one from Kent. If you post it, and It supports your position, I will add it to my list of Historical references in support of the jus soli interpretation.
I am also familiar with this:
1922 US Assist Solicitor General, Richard W. Flournoy, citing ATT’Y General Black.
"Attorney-General Black, whose opinion of July 4, 1859, concerning the case of Christian Ernst, a naturalized American citizen of Hanoverian origin who was arrested upon his return to Hanover, has become a classic on this subject. It seems worth while to quote from this notable opinion:"
“The natural right of every free person, who owes no debts and is not guilty of any crime, to leave the country of his birth in good faith and for an honest purpose, the privilege of throwing off his natural allegiance and substituting another allegiance in its place—the general right, in one word, of expatriation—is incontestible. I know that the common law of England denies it; that the judicial decisions of that country are opposed to it; and that some of our own courts, misled by British authority, have expressed, though not very decisively, the same opinion. But all this is very far from settling the question. The municipal code of England is not one of the sources from which we derive our knowledge of international law. We take it from natural reason and justice, from writers of known wisdom, and from the practice of civilized nations. All these are opposed to the doctrine of perpetual allegiance. It is too injurious to the general interests of mankind to be tolerated; justice denies that men should either be confined to their native soil or driven away from it against their will.”
I'm sure you've seen the writings from Kent that were quoted as part of the Wong Kim Ark decision, so I won't bore you with those again. But let me direct you to this from Volume 1, Lecture 13, "Of the President":
"The Constitution requires that the president should be a natural born citizen, or a citizen of the United States at the time of the adoption of the Constitution, and that he have attained the age of thirty five years, and have been 14 years a resident within the United States. Considering the greatness of the trust, and that this department is the ultimately efficient power in government, these restrictions will not appear altogether useless or unimportant. As the president is required to be a native citizen of the United States, ambitious foreigners cannot intrigue for the office, and the qualification of birth cuts off all those inducements from abroad..."
Kent uses the terms 'natural-born' and 'native-born' interchangeably when referring to the qualifications for president. Since he obviously believes that there are only two forms of citizenship, then the question becomes what he defines a natural born citizen as. In Volume 2, Lecture 25, "Of Aliens and Natives" it is clear that he believes that people born within the U.S. are natural-born citizens, regardless of the citizenship of their parents.