One thing i have always looked into incorporating into my modelling, is working with modular models.
I feel like this method of working would be a new challenge when creating the buildings, and also speed up the process of the workflow.
I found some links on how to create a modular work flow, and i am excited to get the go ahead with art style, and start creating some building fronts.
http://www.philipk.net/tutorials/modular_sets/modular_sets.html