Well I see the new ecomotives coming out of Seat's garage with 15" and even 16" alloy wheels, don;t see why mine couldn't.
On the Ecomotive by experience it takes a lot on the way you drive and preserve your energy.
my fear is about loads on the bearings, I already have a bad camber on rear wheel, have to put new stud.
bigger wheels will overcame a bit that
problem of bending studs, etc.