Design themed Logos across 3 websites!

comparehouses.com.au; compareapartments.com.au, compareland.com.au

I am a property professional, with over 20 years experience, looking to provide a service to people looking for a new block of land, house or apartment. I want to provide the "Choice.com.au" for property, providing advice, explaining hidden costs and evaluating land/houses/apartments on equal criteria when buying new property to make the big decision easier. The service will be independent and not linked to any developer or builder.

The target market is Australia wide, focused on the major cities. Age group will be from 18 to 65 years old and cover singles, couple and families, and catering for both males and females. They will be both 1st time buyers as well as buyers upgrading from an existing home.

I am looking for 3 logos for the 3 separate websites, but which have a common theme between them.

The 3 websites:
- comparehouses.com.au;
- compareapartments.com.au, and
- compareland.com.au

are all about evaluating new products on the market so buyers can cut through the developers "sell" make a more informed decision before buying. The sites will also provide useful selection criteria to buyers inexperienced in purchasing property.

An individual Logo is to be simple and preferably only use 1 or 2 colours. However the colours can be different between the different logos.

The Logos need to be professional and easily recognizable.

File types for the logos need to be suitable for websites.

An example of themed logos that I like are logos used in:
http://www.carsales.com.au/
http://www.boatsales.com.au/, and
http://www.bikesales.com.au/