Now that we have the ability to mod in new units, the current requirement of only using a fixed set of UNITTYPE flags limits the ability to make new factories/fabbers that only build specific units, without those units potentially appearing in the build queues of the existing PA factories & fabbers. For example, as part of the PATA mod, I would like to create a separate vehicle factory that only builds TA units, and those units should not appear in the PA vehicle factory. A simple way of doing this would be including "UNITTYPE_ARM" or "UNITTYPE_CORE", and including this in the relevant build string of TA construction units & factories. Attempting to use a custom UNITTYPE value merely causes an error in the log and prevents the unit from being loaded.
You might be able convince the galactic war code to do that in single player. There are separate unit lists and unit definitions with .ai and .player extensions which are generated at runtime and sent to the server. I don't know if those tags are required or if you could use any tags you like. Server mods followed so close on the heels of GW, we never really dug into the possibilities.
