I have been doing the research for this, and the hard part is the Lidar scanner. This is the smallest and cheapest solution I have found:
It starts at 120k, and that doesn't include the drone.
Here's what can be accomplished, although the technology is currently used for geospatial imagery, like surveying and real estate:
I'm going to do more research to see the viability of making a homebrew Lidar system, that could be the crux of getting this into as many hands as possible.