i don't think we need to cap anything, personally. i mean, i have yet to actually see someone over 100 i just know it is possible and am trying -- just like everyone else is welcome to try
also, people cant necessarily control what number the game gives them and numbers don't mean squat next to knowing how to play the game.
you can also finish a career faster than 12 hours by simply waiting to allocate your sparing points until they reach higher numbers -- rather than allocating them after each sparing session. On my guy that i got to 97 (without any training camps) i just held back his points until i had 3500 to distribute.
Whitehorizon: KOs get you the most points in sparing i think. throw bombs, don't worry about your stamina.