I am currently doing this scripted via EAs for zero touch lab deployment using DEP.
But it would be really really great if there was an easier way of having devices pull data from another source during enrollment or inventory collection. Almost all large organisations have an Asset Database with devices stored by serial number and with a lot of extra useful information included.
Some kind of standard request where it passes the serial number to an external database server and is returned a bunch of fields, then have it so you can make EA references to those fields.
The machine could then be immediately provisioned for it's intended task and it would be much simpler than having to do fancy stuff with EAs or API access from the other end.