I started having foot pain mainly this year on the balls of my feet. I noticed that on our local mountain the longest run is 5 minutes and I never had a problem. But we went to Park City this year and one run was over 10 minutes and around the 10 minute mark the balls or my feet were numb and my toes then went numb and I had to stop and rest my feet and then continue. It happened on every "long" run we went on. Short runs were not a problem.
I then came on here and read about getting snowboard socks. I have really wide feet (Triple E) and usually wear just the thinnest socks I could find because my boots were already tight. We came back from Park City and I tried the snowboard socks and I didn't have a problem. However, we are back at our local mountain which is only a 5 minute run. When we went to Copper Mountain last year for the first time I was starting to have this problem also on the bottom of their longest green run. So I wasn't sure if it was the socks or just the long run that we were on.
We are going back to Park City next month and I can't wait to see if I will still have the same problem. I also notice that the more I ride the cat tracks on my toe side (I'm regular) the worse the pain was. Long traverses on my toe side and the pain would start and boy, once it started it just got worse and worse to the point that I had to stop and rest and then start again.
My boots are laced loose as are my bindings. I feel for ya!!!!!
Your pain sounds like exactly the same thing I am experiencing. Long cat tracks that force me to spend most of my time toe side absolutely kill me. In all other respects my boots seem to fit great though: no pressure points, not overtightening them, no problems with heel lift, toes hit the ends but are not cramped. And the fact that I've never had this issue during any other activity, even when my feet are crammed into my rock climbing shoes or I'm carrying a 30lb pack during a backpacking trip, makes me skeptical about it being any kind of medical issue. I never had this issue with rental boots...but I was a very beginner rider and wasn't riding nearly as hard (or spending much time toe side) when I was renting, and I had plenty of other issues with the rental boots that I don't have with my current boots.
Let me know if you find a solution! I've tweaked my bindings a bit since the last time I was out (because the way I set them up for my new board seemed to have made things worse) but won't know if it helped until Sunday or Monday.