There are plenty of dual and triple outlet adapters, but I've not found a plate configuration. I did get some years ago another single plate version, intending to one of these days run wiring to install it next to the copilot seat. Multi-outlets won't rid us of trip-hazard wire snarls anyway.
As an alternative, I got a 110 to 12v cord extension at Camping World, so at least 12 v. devices could access power while on the road throughout the coach via genset or inverter as appropriate. You might give that idea some consideration.
Joel