Yeah I've done it several times. I think the oddest one was when i played FF8 and was level 100 before even entering the fire cavern....when my friends saw that save file they were quite suprised. It took like 40 hours of just random battles to do it. Also pretty much every other RPG I end up at insanely high levels quite early, it's just that FF8 was the highest I went so early into a game.