This answer explains (very nicely) the justification and practice of those who consider themselves followers of the Rambam, as opposed to any other opinion. In the cited responsa of the Beis Yosef, he is specifically addressing those who become followers of the Rambam.
I am unaware of "Rashba-ists," "Halachos Gedolos-ists, "or "Tur-ists," even though they all have their own works of systematized Halachic codification. I am unaware of "Shachists" or "Aruch HaShulchanists."
This question asks why the phenomenon exists only with respect to the Rambam.
I am wondering if there is any reason why it is only allowed with the Rambam. Is this practice of following exclusively the Rambam limited to the Rambam, or could someone, if so inclined, become an "Aruch Hashulchanist" even though they are, for arguments sake, Chassidish, or Syrian, and have no Aruch HaShulchan-related mesorah?