This new thing looks promising:https://cutlerkeys.com/(See the video of pianist, who cannot ordinarily do the harder major 10ths, play St. James Infirmary -- "Dr. John style, full of solid 10ths"
Two observations:1) the range is narrow, something like the middle two octaves2) every single chord seems to be "white key" chords. What if you get something like an F# chord which is all black keys?