This board:

• Is tiny, less than 10x10 cm for each half, making it easy to carry in a point-and-shoot camera carrying bag.
• Can be made wired or wireless. The wireless version (the one I built) only supports two thumb keys instead of three on each side to leave space for the battery.
• Is cheap (as far as split keyboards go): the whole build cost me less than 90 euros with shipping. The reversible PCB greatly helps with this.
• Can be modified to fit your hands: the four stagger values (pinky to ring, ring to middle, middle to index, index to inner) are defined at the top of the ergogen YAML file and should be changeable without having to worry too much about the rest.
• Supports Kailh Choc hotswap sockets for the switches.

GitHub repo