Typically I shop once a week, and may buy 16-20 bunches of bananas. I guess this would be between 100-150 bananas for a week.
But I eat a variety of fruits. I buy a lot of boxes of mangoes and peaches at Costco, which are also pretty cheap. I also buy cantaloupe there, which taste great after a hot run, especially after putting the cantaloupe in the fridge.
Usually the bananas at the grocery are not ripe. I need to let them sit for a few days before I eat them. So I plan ahead, and buy them a few days before I'll need them. Or I'll eat some other fruit for a day or two while waiting for the bananas.
Someone here mentioned constipation. I think that can happen if you eat too many unripe bananas. They need to have brown spots, and the top should come off easily. When I eat ripe fruit, I never have any problems with this. Unripe fruit contains starch. Ripe fruit contains sugar. The sugar is much easier to digest.
As for the youtube thing, what is the big deal? Haven't you seen those guys eat like 70 hotdogs in 10 minutes? That's amazing. I am talking about just comfortably eating 20-30 bananas (which have a lot more water than hot dogs) over the period of about 1 hour. Ripe fruit is really digested very quickly. I think by the end of the hour, the fruit I ate at the start has already left my stomach.