I wouldn't call some bloodlines "tainted". I see it some bloodlines as "incomplete", such as the Uchiha, Senju, Hyuuga and Otsutsuki, for obvious reasons. Every other bloodline are offshoots are even more "incomplete" from the originals.
Kekkei Tota are taught, and aren't limited by bloodlines. They are usually composed of three different elements, with Dust Release being composed of Fire, Wind and Earth. And with seven basic elements to work with, there can be 21 different combinations to make, which means 21 different Kekkei Tota that can exist. But I haven't really seen anybody try to throw the the Stand-Alone Elements, such as Dark, Crystal and Steel Release, into the mix. So there can be more, if people are willing to stretch their imaginations (and chakra capacities).
Of course, somebody can just go out and try to make a Kekkei Tota composed of four elements. And then they can say that their Kekkei Tota is stronger than others because 4 > 3. But it can be called out that it would be even more chakra taxing and requires even more concentration. Or voided completely since the only other thing in this hypothetical situation that can beat it are the Gudoudama.