So true. In cycling, there's an expression - "light, strong, cheap. Pick any two". Building yourself helps, but even then, a few kappalites or equivalent, plus a proper cab or two to mount them in, won't be cheap. Any lightweight head with sufficient power won't be cheap, either, even used. The most economical way to lighten the load is probably to use ones existing head/amplification (unless it's a SVT) and build some lightweight cabs. Even the heaviest head won't weigh anything like as much as an old school cab.