Again, what does "mega router" mean.
There are PCs designed for routing, they don't look like PCs, but like network switches.
You just described an x86/PC router 
If you want examples, google Barracuda F12, Cyberoam CR15ing/CR25ing/CR35ing, Trustwave TS-25, Sophos SG/XG.
Study So you have 500Mbps-1Gbps fiber and need a router READ THIS FIRST