Hallo !
I can imagine, that a 3-5 ethernet module would be really great
to build a self-made OpenWRT box. A multi-ethernet module would
give you many options.
Thanks anyway,
Manfred
Something like a Mikrotik, but with bootable SD card and without RouterOS? Yes, that could be nice. Additional SATA controller with at leatst two ports could be also great, because you can make a router/NAS combo.
BTW, you can use the OpenWRT on some Mikrotiks, but the procedure is quite complicated (eg. you have to use a serial console and own TFTP/BOOTP server).