This circular saw is battery-powered, so no need to bother with cords and such. It can cut through 46 millimetres of wood and weighs 2.8 kg, so it's not that heavy to carry around.
From ManoMano
Panasonic - EY45A2XW Universal Circular Saw 135mm 18V Bare Unit PAN45A2XW32
ITS
Panasonic EY45A2X 14.4V/18V 135mm Multi-Purpose Cutter - Body