I have sold over 30 Real Estate Logos in the past 2 years, and my experience in that area lead me to the conclussion that your request to use more than rooflines is an good one. In todays web based market, you will need a versatile ICONIC emblem to represent you. It will need to work two ways: On top of the wordmark, and beside the wordmark. It also needs to be unique, and many roofline logos fail to set you apart.
It also needs to look sharp from a distance on yard signage etc..
I have a selection of entries that I hope do that very thing. I have submitted them in both layouts.