(Version 2 shown here)
I actually bought the first version of this one-handed keyboard+mouse years ago. It was plugged into the PS2 port on a Linux box, and came with an optional velcro strap to keep it in your palm when chording particularly difficult key combinations. It was hard to learn the chords, slow, and painful to use! They’re still in business (apparently with Google encouragement/backing), and up to Version 3, according to a Gizmag review I just saw.
The latest version can work wirelessly, and supports key remapping. Looks like they’re marketing it to work with Google Glass and smartphones. But it doesn’t look like they’ve paid any attention to key feel in all this time. As the reviewer wrote: “While the buttons trigger smoothly without sticking, typing does have the feel of poking at a remote control.”