Comment by epakai

FriendlyElec's NanoPi M4 has a 4-port hat. Their NanoPC T4 has a M.2 PCIe x4 that has potential to be adapted to full-size slot.

Pine64's Rockpro64 has a regular x4 slot for expansion cards.

I've seen lots of upcoming Pi CM4 options, but don't know what's out yet.