Your arm length seems huge. If it is 30cm axle to tip your robot will be longer than some heavyweight bots. Due to leverage I'd recommend going wider rather than longer. This might screw with your tracks idea though.

Yeah it is 40Nm at the axle as is. But if you get that arm down to 20cm it is 26Nm for eg.

I got there using this calculator
http://www.sensorsone.com/force-and-...ue-calculator/

You also won't need to hold all the weight at the exact length you seem to be designing to scoop and lift so you need a lot less power. Iirc the ballpark figure is half the weight to just topple over a robot.

You will need a torquier motor(s) to achieve this, yes. But the difference seems to be less than you thought, especially with a design tweak.