Consider the Yamaha P85 piano which weighs 25 lbs with an 88 note weighted graded hammer action....with speakers, no less.

I think it could be possible to do a weighted 76 note arranger and keep the weight down to around 30 lbs.

Whether it would ever be made is another thing.

Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.