PCIe switch "hat"

Maybe my question is not in the right topic, but let me try.

is there a way to make a special “HAT” for BPi-M4 which actually expandes its PCIe connector to 2 or 4

The ASMedia asm1184e would be great for this I think. and a ribbon cable connected to the mainboard mini pcie connector.

what’s your opinion?

The PCIe of M4 can be used. we have been tested for RTL8168e(PCIE to gigabit), but not for ASM1184. It should be edit driver