Here are a few ideas I don't have time to pursue.
1. Make extruder-type 3D printing work better by heating the material just laid down, just ahead of the weld point. Use hot air or a small, maybe 5W laser diode. Use 3 heat points 120 degrees apart so you can heat ahead of the direction of travel. Modulate the laser with pulse-width modulation, then read the temperature during the off period with two photodiodes with different IR filters. Go closed-loop on the temperature.
2. Initial application for automatic driving - airport auto rental. Book rental in advance. When customer's phone shows up at destination airport, dispatch car to terminal, timed to show up just after luggage pickup. Use phone to direct customer to car. On return, customer drops off car at terminal, and it head back to rental lot on its own. Self-driving is limited to low speed in known areas. Expand system by adding parking garages at likely car rental destinations, such as convention centers.
3. Conference room automation. Video projector should have camera, find screen, put up test pattern, focus, correct for parallax. Room lights should sense projector/external lighting situation. Microphone system should automatically track speaker from a distance (this exists, using a hemisphere with a large number of microphones and a lot of CPU power) without any effort by speaker. Video feed of talks and classroom should have people tracking and automatically generate a useful video feed. The whole thing should Just Work. Internet of Things crowd, get busy.
4. Integer overflow, both signed and unsigned, should trap in CPUs. If you want modular arithmetic modulo the word size, you should write "x+= (x % 65536)", and the compiler should understand that as an idiom, generating an cheap unchecked unsigned add.
5. Set import duties to recover about half the wage difference between the exporting and importing countries. This escapes the "race to the bottom" problem. Half, so as not to have too much protectionism. Politically difficult, but the current ratio for the minimum wage in Shentzen to the US is 5.6. China is getting close to where this is feasible.
Idea generation is easy. Implementation is hard.