My vote goes for the Mezzo. It truely is a fabulous bag. I am 5'3" and I don't think it looks too large at all. It's all up to what you feel comfortable carrying. I tend to lean more towards large bags because I lug a ton of things with me to work.
I am 5ft myself! There are no LV shops near me, so I have to buy online from their website. The piano is definately too small for me and I have just sold it on ebay! So I gues the next bag up is the Mezzo. Is it heavy though?
Nope, not heavy at all. That's one of the things I love about it. And the handles are comfortable. It's just a bigger version of your Piano. If you liked everything about the Piano except for the size then you will love the Mezzo.