Back in the NI-CAN days, there was a handy development tool which was the usage of two virtual CAN ports, ports CAN256, and CAN257. If you wrote a frame on one, it would be read on the other, and vise versa. Other CAN hardware like Vector, and Kvasar support virtual CAN hardware which does something similar, where initial development can be tested before having access to the hardware.
This idea is to add virtual hardware support for XNET which supports this same feature. it has been talked about in a thread here several years ago, but nothing ever came of it. Adding support for virutal hardware for CAN, LIN, Flex-Ray and any other XNET hardware would be a great development tool, and enable the testing of the expected handshaking of software, with simulated communications.