I've been considering building my own router for a while now and am looking for the right SBC, or maybe even super small motherboard. I considered using one of my old PC's but I want something more compact. I'm trying to find something as expandable and modular as I can and nothing I've looked at thus far has really fit the bill. I'm thinking of something that can be easily upgraded so I don't need a new router every few years. Maybe something with a lot of PCIe or M.2 slots. The idea is I can just add cards to expand functionality (ignoring software for the time being). For example, if I decide to have a cellular backup, just add a new card. If I need more parts and don't want to add a switch, just add a new card. If a new Wifi standard comes out and it's time to upgrade, add a new card. I've looked at ODYSSEY-X86J4105 and it seems promising but I don't know if it's expansive enough. I'm also concerned about any potential bottlenecks. I was even thinking about something like a cryptomining motherboard with all those PCIe slots but I don't want something that big and a full size PSU. Any one have any ideas or suggestions?