I can't check my reference books for now but I seem to have read "krisses" as the plural of "kris" in many books written in English such as those from Frey and Van Duuren?
Regards
Yep, i've certainly seen that spelling. But frankly it sounds funny, like you are lisping when you say it. I'll stick to plural keris myself under i find a point where it doesn't proper communicate what i am trying to say. Just my own 2 keris there...