Being honest, 1kg is a nice number. Obviously it's purely due to metric/imperial differences that we get things like 1.362kg when converting from US weights. But I will build one regardless of whether it's 1kg or 1.362kg.

The draw of building one for me isn't the weight limit, it's more to do with the (hopefully) active weapon requirement and the varied terrain. I'm putting my 6WD with lifter idea on the backburner for now though, just going to try a basic one using surplus servos for a first attempt, maybe with a grab/lift arm on it.