Hi EdwinLucasBus,
I'm a logo/identity design specialist based out of Toronto, Ontario Canada. I have helped many businesses achieve their ideal corporate identity, from logo design to the development of company assets, signage, and other print materials.
You mentioned a sketch of your design prior to commencement of the project. I can provide this for you once we begin the project, as I'm a firm believer that working with the client is first and foremost, an important process when developing corporate identity. Two-way communication is important when establishing the communication parameters of the logo and design, execution, coloring, scalability and implementation to other assets (such as print, web, etc).
A design brief is absolutely necessary, as it is an important part of understanding not only what values/views ISTA as a company will hold, but also what message will be conveyed.
Your description of large buildings as part of the logo is a good idea, but I believe it's execution will be important in separating it from the hundreds (if not thousands) of logos out there that contain the idea of large, looming buildings for real-estate. Let me know if you are interested in discussing further. Thank you.