Should I make a 'start with Spidertron' version of this scenario? I would have to alter it a bunch. You would end up with Spidertron with a couple of roboports a power supply (probably a bunch of solar panels) in Spidertron's equipment grid, and all the other BNW stuff (including all the items normally initially placed) in Spidertron's inventory.

I think I'd add a couple of filter inserters so you could remove specific things from Spidertron's inventory more easily, since equipment grid roboports won't do logistics.

Inserters don't work on spidertron, but there's a logistic chest equipment grid mod that works with filtered slots in the trunk.

https://mods.factorio.com/mod/EquipmentGridLogisticModule

Filtered slots get filled with what they requested (requestor chest) and unfiltered slots get emptied (active provider)

Edit: "yes" (to the original question) :)

I was thinking also of modifying the scenario's win condition to be sending a special 'base seed' object that's built with all the original materials you get, plus some of the stuff used to build a statellite, plus some extra rocket fuel (for landing).

Basically, the premise is that spidertron is a self-replicating machine design to build resource extraction factories all over the universe for some race.

I don't like the idea of the equipment grid logistics thing. :-/ If everything in Sipdertrons trunk was buildable, you could technically empty the trunk by building it all, even if inserters didn't work. Hmm...

Edit: Except the bots. And also loading up spidertron to go out and build elsewhere. Hmmm....

I was thinking also of modifying the scenario's win condition to be sending a special 'base seed' object that's built with all the original materials you get, plus some of the stuff used to build a statellite, plus some extra rocket fuel (for landing).

The win condition could be to launch another spidertron. You could modify the map to not generate any fish. (since there's no engineer they're useless). That would require 2 rocket launches. 1 to get space science, and a second launch to get a fish to build another spidertron. If you used the new ship crash site you could have that be full of the things that that you want the player to start with.