Not a common bonsai subject, but I am going to make one anyway. Leaves are big, but in pot culture, not THAT big. They reduce to 1/4-1/5 right away. In comparison:
Leaves and stalks both reduce easily. They will never be small, but they are really beautiful nevertheless.
I have had a few A. platanoides, but I have tried to make too small of them. Silly, but I have tried to make 25-30 cm high bonsai. It has even worked somewhat, for lets say 4-5 years, but then they just give up and die. They get weak and some kind of mold will attack.
Now I will try somewhat bigger tree, perhaps 40-50 cm high. I don't seem to have any interest in bigger trees than that. I think oversized pot would help to maintain tree's vigor.
That particular tree is perhaps not very good, but will do until I find something better. To justify bigger pot I would like to have a tree with lets say 15 cm trunk diameter.