IO540.
You say: The panel layout needs to be designed from scratch for these large LCDs but this happens only on turpoprop class and above. The rest just bolt them in.
This was absolutely true at the time of your post. Not so with effect of yesterday.
Columbia are now offering their 350/400 with a "FULLY integrated" G1000 FMS.
What is different to the other G1000 systems out there?
Supports AFD/DME (integrated).
FMS "ready pad" in the arm rest.
Digital autopilot with CWS and FD.
Cannot stall or overspeed aircraft with AP engaged.
Screens "autoreversable' ie switchable.
Trims and oxygen now on the MFD.
TAWS on MFD.
Plus a host of other stuff.
Impressive