Imagine the smallest hexapod that could grab, carry and lay a single brick, then coordinate a huge swarm of them.

Or better yet: imagine the smallest walking/climbing platform that could carry a robotic arm just big enough to take a brick and pass it on, then coordinate many of them into semi-static bucket brigades for bricks and mortar that could form an ad-hoc power grid to solve the battery issue.

The main innovation tasks/requirements would be cheap volume production of the swarm elements and intelligent planner software to automatically derive a work plan straight from the CAD data (or else project setup/customization would be prohibitively expensive). The beauty would be scaling: need to build a bigger structure? Add swarm elements. Need to speed up the schedule? Add swarm elements.

yes that's the one. where do you live? let's create a startup.