A front camera, similar to the same HD camera as in the back would resolve almost all issues with parking sensors. It’s not the same but could help a lot, particularly to avoid scratching the front bottom.
Would involve the cost of a camera and some kind of video switcher and a bit of software. We estimate the retail cost to be less than $200 if produced in high-volume and integrated into the Model S. Seems quite doable. One concern is how to keep the front camera clean from bug hits and dirt.
One third-party front camera solution was available at TMC, which displays on the Tesla screen. Parts cost is about $450.
The Cybertruck prototype includes such a camera.