I've put some thought into this.
First, the laws are changing to integrate UAV's into the air traffic system. Even with maximum effort, the change will take 5-10 years.
The technology is progressing faster than the laws. There are already purpose built UAV's and a few 'upgrade' kits available for existing manned air craft. Old F-4's have been used as missile targets for years. I've also seen an unmanned A-10, and optionally piloted C-208 and AH-64's. There are even plans for unmanned B747's and C-5's for trans pacific routes.
That said, you can still expect 5-10 years for any large scale deployment in the civilian market and 5-10 more for general acceptance.