The keymouse, is a mouse and keyboard combined into one.
It came out around 2018.
It's expensive. $500 as of 2018-11-18
Keymouse Comet, came out around 2019 March.
This doesn't seem like a good design.
When you have a symmetric keyboard, a lot nerds naturally think the center is the proper place to put the trackball. But that's actually a unnatural position with regards to hands.
The proper position for trackball, is actually near the thumb for a small trackball, or on the side for large trackball.
Where to Buy
If you have a question, put $5 at patreon and message me.