For a different jumping-off point: check out rctestflight on youtube [0]. They're designing and building minimal custom drones (boats, gliders, tracked etc.).
Seconded, except maybe one I could build that could drop a payload? I was thinking of using a drone to drop off a raspberry pi of whatever model. Maybe one that had a few sensors and a solar/battery combo. It would be a cool way to install a wireless security system.