Anyway..
Abbey of the Sword/Essembra: The abbey lies five miles southwest of the large town of Essembra in Battledale. Beneath the abbey is a portal to Sigil perhaps, since they are so pressed by the drow, they could convince Essembra to open a market in their town to cater to extraplanar travellers that may pop out of the portal in order to raise money. They'd need some form of help to pull this off, possibly extraplanar itself.
Thayan Enclave: Not really an actual location, so much as a hook. Perhaps some Red Wizards have decided to open a portal in one of their enclaves for some extra business. They'll take it upon themselves to keep things in order and keep the more exotic/dangerous being out of whichever city.
Enclave Locations: Athkatla, Baldur's Gate, Calaunt, Calimport, Cimbar, Hillsfar, Hlath, Hlondeth, Innarlith, Iriaebor, Marsember, Messemprar, Mulmaster, Procampur, Ravens Bluff, Saerloon, Scardale, Scornubel, Soorenar, Telflamm, Waterdeep, Westgate, and Yhaunn.
I'm only providing contingencies for the free-for-all option, instead of destroying another locations original concept later. So, if you don't like them, don't tell me about it.