Kyparissia!
As a matter of fact, there really is another Kyparissia! It's a small village in the East of Neleus' kingdom and exactly what we've been looking for. The village of Kyparissia is situated in a valley through which the river Alpheios flows. In the valley are lignite mines, which is used to fuel the local power stations. In the course of the mining an ancient city was discovered and excavated.
The excavated city is huge and dates from after synoecism. It's right next to the village of Kyparissia, which points us to a second Kyparissia! Across the Alpheios lies that other big example of synoecism, the city of Megalopolis, and now we've discovered another example in the second Kyparissia. This obviously fits Homer's sequence much better. We've found his Kyparissia!
Now we can start our search for the third city in the sequence, Aipu, which must be located somewhere between Thryon and this second Kyparissia.
The excavated city is huge and dates from after synoecism. It's right next to the village of Kyparissia, which points us to a second Kyparissia! Across the Alpheios lies that other big example of synoecism, the city of Megalopolis, and now we've discovered another example in the second Kyparissia. This obviously fits Homer's sequence much better. We've found his Kyparissia!
Now we can start our search for the third city in the sequence, Aipu, which must be located somewhere between Thryon and this second Kyparissia.
A second
Pylos
Arene
Thryon
Aipu
Kyparisseis
Amphigenia
Pteleos
Helos
Dorion