I spent some time working with a fascinating engineer by the name of Greg Priest-Dorman, who for various reasons uses a pair of chording keyboards. He attaches

I spent some time working with a fascinating engineer by the name of Greg Priest-Dorman, who for various reasons uses a pair of chording keyboards. He attaches one to one hand/wrist, and the other IIRC is loose for setting on desks. With this setup, he quite successfully types standing, sitting, walking around, etc.