Something I just found online -- the original 1857 Charter of Congregation Beth El Emeth. This was a Mikveh Israel breakaway congregation in Philadelphia which lasted about 50 years. It was formed by supporters of the Rev. Isaac Leeser, after Rev. Leeser departed Mikveh Israel. Section II of the Charter set forth that "The form of worship shall be that of the Portuguese Minhag according to the Prayer Book originally issued for the use of the Congregations in London and Amsterdam."The Charter was signed by people bearing illustrious Sephardi Tahor names such as Mayer, Goldsmith, Sternberger, Bloomingdale, Liebir, and Gellick.