What I do to lengthen my music stand is place a regular music stand next to it.
It may not be in the center but I can place at least three sheets of music on it.

I also rewrite the music and make the notes bigger [for easier reading] and then paste that on a thin piece of cardboard for stability so that anyone doing a polka and dances by my keyboard the music does not fly off behind them.

As for Technote coming out with a wider stand you can bet it will be overpriced like most of their products.

Alex