A while back I was thinking of doing something like that as an annual safety inspection. Test GFI's, smoke detectors, open the main panel and check connections, and look over the service outside, etc. Then try to upsell devices like USB receptacles, dimmers, LED bulbs, whatever. Depends on the age of the house.
I used to know a handyman who had a trifold brochure that he handed to a customer when he was first called on a job. The brochure was a checklist of many things that could need repair in a house. He asked the customer look it over while he was there and to check off anything else that they could think of. It seemed to work well for him. He had to keep a truck stocked with tons of stuff but he made one small job turn into a larger one. He also used flat rate prices which made it easy to estimate, invoice and get paid on the spot. At that time, he used a Blackberry to keep his prices. He said that customers would trust his prices because they were on a device, and they believed were getting the same price as anyone else, rather than getting a hand written estimate which can appear made up at the time just for them. As electricians we have to get creative in this area.