Wire wheel weed eater - video

[Toolmaker51]

Not just resembles, near copy of a full size street sweeping truck. Not sure [at 5 in the morning] how to procure/ construct brush head. But a vertical gas engine, some type of outboard bearing and drive belt. this is very buildable. I see need of a third [not visible in vid] wheel forward of brush ideal for balance, height and stability.
The deck and brush could also be pitched a few degrees laterally to reduce contact of inboard side. Compare this to fly-cutting, when a mill head when not trammed in accurately.
A poly tank and solenoid valve to dispense weed killer selectively along line established by brush periphery would top this off.
Regular trimmers only do a so-so job on pavement cracks, brick pavers etc; string and surface are too close to parallel. This semi-perpendicular brush is near perfect.