Try as I might I cannot find any reliable information as to when or if this supplement will be released. It seems unlikely that the gnomes at Forgeworld will ever sort things out.
As a result it would be an interesting winter project to research my own and publish them here. As a starting point I'm considering the Seleucids for the simple reason that I have the Montvert Seleucid publication with its description of the Daphnae parade in 165BC. The only fly in the ointment with using this era is the conversion of Argyraspids to imitation legion, which is just to Roman for my tastes. So a better option may be to look to the reasonably well represented Raphia campaign of 217BC as a genesis. This may well be as far as my current enthusiasm carries me, but further down the line an Antigonid list may appear but they're a bit light on decent cavalry to really grab my interest although theres quite a bit of published stuff on Cynoscephalae and Pydna to work with. Lower still on the list of priorities would be the Ptolemies; despite my best efforts I've never been able to shake off an irrational dislike of them.