[xyzzy123]

I think the most reasonable near-term approach "if you had to do it" would be reverse engineering and virtualities, but please bear in mind it was a hypothetical to begin with.

I expect the number of inputs to spider sensorium would be low thousands of analog inputs. To be clear I can't cite a reference for this.

Yes it seems intractibly difficult on paper but spider hardware can do it.

It's hard to rate what we'll expect from self driving cars on the flatworm to spider spectrum (probably closer to the flatworm end, but the cameras add an interesting dimension), but clearly reasonable yet ambitious people believe these problems are tractable with sufficient effort.