I have contacted Shanghai No. 17 Radio Factory and they still produces 2DW23x series. If I buy those for you here is the prices:
* Price: 75 US cents each, regardless of order size
* 50 diodes each pack
* Delivery from factory to my home: 2 dollars total if total order is less than 50, free if more.
* Delivery from my home to your lab: 5 US dollars for less than 2kg
If you are interested in buying them fresh from the factory, PM me your address and order. I will accumulate it and order it from them directly.