I know Urban Geography provides that, but are there any other related fields where I basically get paid to study cities, their designs and compare them to other cities, etc?

Urban planning

errr sorry I don't really know what else could be of use to you. Urban planning encompasses alot of what you are looking for.

Here at Pitt we have an Urban Studies Program.

Link (http://www.urbanstudies.pitt.edu/)

Go to Australia or Asia.

I am currently an Urban Studies major at the University of Calgary. Awesome program with potential so doing whatever you want with respect to urban issues or cities in general. I'm working towards graduate studies in architecture, so urban studies is a great program as a foundation. I've people do anything from architecture to land use planning and city planning with this degree. Depending on which courses you choose, it's really up to you.