Not a splitter, but this is what I developed to run a full dual Skyview system and avoid most of the issues relating to wiring.
The board was developed by me on an online site that gives you a program and then you can order the results. I got 4 at about $40 each not including the solder in type Dsubs.
There are two 25 pin Dsubs on the board. One for each Skyview system. Twenty five of the wires on the display 37 wire cable go to the Dsub including all the power inputs (two for ground and power because the current capacity on a single Dsub pin is 5 amps). The board connects the things that need to be connected together with two displays like the 5 RX & TX, GPS inputs and power, transponder and ADSB stuff and some contact inputs. The power supplies are separate.
The six 9 pin Dsubs go to components or the airframe. They contain all the wires necessary for the component resulting in a dedicated cable to the: Transponder, ADSB Receiver, GPS, dimmer and audio circuits. One is the unused RX & TX and some contact inputs. One plug is the airframe inputs to the system: Power to each display, power to transponder and ADSB receiver, and inputs such as transponder ident switch.
On the corners of the board are 4 ground tabs that provide the system grounds and ground to the dedicated common point grounds that are the two 37 pin dsubs. There are also points where jumpers can be used to correct errors in the design (one in use) or make other direct soldered wire connections.
In and working in my -10. I also have a Dynon Network connector mounted just above the board. Makes for a mess of cables, but is a simple solution.
Dynon and Advance have these also, but you have to buy a complete panel from them, they don't sell them separately. Theirs also include a bunch of great things like trim control, power to aircraft lighting, and much more. They should sell them to the public.