Alright, there are alot of misconceptions about cronic cardio that I see. First off is people think no cardio, but if your idea of play involves running, do it, just do it as play (like once a week). I know Mark enjoys ultimate frisbee, and that is actually cardio, just keep it down to a reasonable level.
Also, you wont miss the cardio so much if you ramp the intensity of everything waaaaaaaay up. A 20 minute workout can have you so drained the next day that you wouldnt dream of doing cardio... especially if you really hammer out the compound lifts (squats and deadlifts), and do your high intensity interval training. When I was a chronic cardio junkie, I could run those miles everyday, because I was always holding back from using everything. For me, Primal is about outrunning the bear, you put it all in like your life depends on it, and when you are done, you couldnt fight off a mouse.
Articles like this may also help you http://www.marksdailyapple.com/jonas-colting/ There are tons of articles on endurance atheletes who want to go primal.