Are any PS2 models that support the HDD still being manufactured?
Yes, but only in Japan. The Midnight Blue model 50000 is still being made and sold in Japan, bundled with a BB Unit, due to how much HDD support is available there. The slim model 70000 is also being made there, and Japanese gamers have been informed to buy the Midnight Blue model if they want or need HDD support, as SCEI has no plans to make the slim model support the HDD. SCEA and SCEE have switched to only manufacturing the slim model, and SCEE never released the gaming HDD, so the HDD is pretty much dead, or doomed to die, in those regions.