An electric sheet cutter is a perfect tool for cutting metal, and easier than using a manual one. There's no cord to restrict you, just make sure you've charged the battery.
From Bosch
Cordless Metal Shear GSC 18V-16 Professional
Powertool World
Bosch Professional GSC 18V-16 Cordless Metal Shear Body Only
ITS
Bosch GSC 18V-16 18V Metal Shears - Body