Replace entertainment system

So we still have the origional entertainment system that came with the MPG. The little square box below the TV with the built in DVD/radio player. What have people replaced this with. We changed out the TV last year but the system is just too outdated. I'm guessing nothing fits that square spot exactly and I'll have to have some sort of spacer to hold it in place. Any suggestions?

This what I did on my radio replacement. The radio does not have a CD player. Purchased the radio and power strip mounted below and used a black piece of plastic as a mounting plate. Install was on a 2011 MPG 185 above the jackknife coach next to storage cabinet. This is where my original radio was.

Jim