The Allium58CAD by Zac Morhous aka zxku is a custom magnetic case integrating a wireless split keyboard and a SpaceMouse. It's worth noting the hand-dyed keycaps too, inspired by Sneftel's post explaining the process of creating his caps for the Gull.
SpaceMouse + Split Ergo Integration: Allium58CAD. I spent far too much time looking all over the internet for a good solution to give me a left hand number pad, and a few macro keys to use with my SpaceMouse navigator. Decided I didn’t like any of the solutions I saw and decided to create my own – Zac.
Keyboard halves of Beekeeb's Allium58 snap to the SpaceMouse base with magnets. This allows it to be used as a unibody split, or as a true split keyboard – as it was intended originally.
