Securing a garage door
The customer was thinking two padlocks, so I'm imagining how I could roll with that. If I did use two padlocks, I'd want to be able to key them alike without having to drill out the pins from the side. After looking around my garage, here's where I'm thinking. I have a box full of long padlock shackles. I could take two of them and heavily striate them with an angle grinder. On either side of the garage door, I could drill 3/4" holes into the ground corresponding to the two ends of each shackle. The ground is either concrete or asphalt, depending on how far the garage floor extends beyond the door. I could then place the shackles in these holes and fill them with cement, allowing the top of the arc to stick out about 3/4". I'd secure a hasp to the inside of the door, possibly with carriage bolts visible from the outside. Then I'd slap a couple of hockey puck padlocks over the hasp and shackle. They'd be close enough to the door to almost fully cover the hasp and protect it from an attack.
But I see a significant vulnerability in this plan. I think I'd just be better off finding a lock that mounts to the inside of the door and slides a bolt through a hole in the track. Mounting it on the door might be tricky, since the door doesn't have sheeting on the inside. Maybe I should buy the fellow a long-range baby monitor.