Hi newmedia, first of all Welcome to WebmasterWorld!
I think you have a point about mentioning SOHO businesses on Google Maps. As a customer I also sometimes use Google Maps to see where a specific business is located, just to get an impression of the size and location. But in the current Internet environment these are things we have to live with. It probably won't take many years before Google will offer some service where you directly have access to map and satellite data for a specific website right from the SERPs, based on address data they have found on that website.
You have to think about what is worse. Google giving accurate data with their map and satellite data where a company is located, or small web companies trying to hide their actual identity and size. From a customer point of view I'd prefer to know who I am dealing with.
A quick look at a decent map will tell me if a location is in a business or residential area, Google just makes it a little quicker.
If it is a problem then get a PO box number. That can have side effects as well. My previous employer collected their mail from the delivery office so the post code for the box number resolved to the delivery office rather than our address. I recall several panic phone calls from visitors who had simply fed the post code into their sat nav rather than open the A to Z.