Good day!
Here is my idea
1) The main thing is that the router should have power supply modules like on CCR1072 (48v + 48v, 48v + 220v, 220v + 220v)
2) The router should have a minimum of 8x10GB (SFP +) and a 2x40GB interface. And so, you can create a router with 8x10GB (SFP +) and a slot for modules with interfaces 2x25GB or 2x40GB or 2x25GB + 2x40GB interface.
3) A CPU that will, without any problems, handle this interface volume on the switching ~ 320/480/960GB router. Because with this amount of data, many will use Mikrotik CCRxxxx as a core router with BGP Full View.
4) You can increase the size of the router by 2U or 3U. Not so much difference between 1U or 2U or 3U.
Best Regards.