There are some pretty small historic hones out there that are perfectly functional for razors.
The celebrated water hone for example often comes in a really small format 5x1. It's more of a stick than a hone. With careful use they work perfectly fine. There are also a lot of coticules out there at 140-150mm x 40mm (5.5 - 6 x 1.5 inches). Perfectly fine to hone on, In fact my own is this size.