Have you ever billed yourself for work you've done on your own stuff? Or the opposite, if you have a personnal backhoe, have you ever had your own business "rent" it for a job?
I once had to do an insurance-job for myself. Drunk hit a pole, lines surged for about ten blocks. Custom machine I had connected to grid power got fried even with protection systems in place. Insurance company just told me to send them a bill.
I know many individuals that own land they lease out to companies they own.