The Duet 2 ethernet is actually aready modelled, see the documentation here for the link to it;
https://docs.duet3d.com/Duet3D_hardware/Duet_2_family/Duet_2_WiFi_Ethernet_Hardware_Overview#h-3d-models
The Duex5 model is now uploaded to our github:
https://github.com/Duet3D/Duet-2-Hardware/tree/master/Duet_Expansion/Duex5v0.11