Adding additional Ethernet MAC/PHY options

Looking down the road I see some applications that would benefit from the new 10BASE-T1L single pair ethernet. (1700Meter, 10Mbps Ethernet over single pair)
Currently, Analog Devices has two SPI devices:
ADIN1110 MAC-PHY - single port 10BASE-T1L
ADIN2111 MAC with switch and 2 PHYs for daisy-chaining.

There is no Ethernet stack on the devices so it is similar to the ENC28J60. The SPI protocol can be configured to support OPEN Alliance SPI or generic SPI. OPEN Alliance SPI is available here: Automotive Ethernet Specifications

It is probably beyond my current capability but is it possible to add a device like listed above and use the network stack that is in TinyCLR or can it only be done on the firmware side?

There is a PHY-only device, ADIN1100, but that would not work with any of the SitCore SC20xxx SOMs. The SPI route seems to me to have the most flexibility, at least with the current silicon options.

There is also a 10BASE-T1S protocol. It is a 25Meter limit but supports multidrop with up to 8 devices over a single cable. So no switch is needed to connect up multiple devices. Microchip has PHY transceivers that support it.

So long question short. . .is there any way to implement the SPI MAC/PHY devices with current firmware?

You can use basic network library

To gain full networking, we would have to evaluate and see the value to all.