Northrop Grumman announced their FIRESTRIKE is ready for sale. A single unit puts out 15kW of energy and weighs about 400 lbs. You can link together 'at least' 8 units and get 100kW of output. Heavy and uses a lot of power, but it's actually doable. Assuming everything works as advertised, this could be put on an armored tank chassis and deployed as an offensive weapon.
http://www.theregister.co.uk/2008/11/14 ... _for_xmas/