Depending on how many you need, it might be easiest to just buy something like this and desolder the connector from it.

E: Looks like /u/AJMansfield_ got his hands on some at some point: https://www.reddit.com/r/ElectricalEngineering/comments/hshw1p/where_to_get_usb_type_e_front_panel_header/ https://www.eevblog.com/forum/projects/where-to-get-a-usb-3-1-type-e-front-panel-header/ might want to DM him.