Aside from the Town, I think the Balenciaga Velo will also work well. The Velo is bigger than the Town and I used mine recently for a vacation trip (plane ride, train rides, and lots of walking) and it worked well.
Second the vote for Velo. City would also work - size in between Velo and Town.
Velo is a great travel and day bag: holds a scarf, water, books/mags/iPad, umbrella, gloves, whatever -- in addition to normal "handbag" stuff.
City would go from day to night better than Velo and would hold more than Town but less than Velo
I love the look of the town but at only 3"deep (front to back), that would only be an evening bag for me!
Length of shoulder strap may matter as well" Velo=adjustable/long. City=shorter. Town -- longer (I think?) like Velo (Town owners, help here?). I have Velo, City and Day - but am coveting a Town. Still would use any of the three I have for travel before using a Town.
Hope this helps!