Routerboard with 48 ports

Is it technically possible for a MikroTik Routerboard have more than the number of Ethernet ports on it? For example, I have a RB5009UPr+s+ and I want to make it look like it has 48 additional ports. I am not talking about hanging a switch off of the on-board ports, but each port can be configured for different purposes, all controled by the RB5009UPr+s+.

So basically a RB5009UPr+s+ with 8+48 ports.

I want to say that in Cisco, this is called a fabric extension. Not 100% sure though.

Can I get this functionality by addting a CRS? If not, what is needed to accomplish this?

Edit: Lets say I had 20 internet connections, each providing an Ethernet handoff. I want to configure the MikroTik to accept those 20 internet connections on ports 3-8 (onboard) and via an external device with 14 ports that act the same way as the on-board ports on the MikroTik.

Imagine a 48 port (or 56 port) MikroTik Routerboard. I want something like that.