I heard about a cap of around 30k for resistances, but I'd like to have more info on that as well. If you find anything, please let us know here!
I'm not sure what values you are seeking for but I can confirm that the resistance is capped at 33000 at V16. You can see someone else's raw data and analysis at https://www.reddit.com/r/elderscrollsonline/comments/3mic08/update_7_armor_and_spell_resistance_mitigation/
or you can see the equations I use for some calculations involved in the game from my own personal testing but without the raw data at http://tamrielfoundry.com/topic/pts-2-1-2-sorcerer-arithmagic/
While most of my equations are based on magic damage, a considerable amount is transferable to physical damage.
Hope this helps answer your question and that you can keep playing the game without having to do too much of your own testing