Do you know what companies are making them? I'd love to take a closer look as I've also been looking for a risc-v rpi alternative.

As is always the way with these things, unfortunately I'm under an NDA until the products are released. However I can tell you the rather obvious thing: We're helping them to understand how to get changes they need integrated into upstream communities (kernel, GCC, binutils, uboot in particular) so that their hardware will boot without patching when or soon after it is released.