analog - BCD Switch Resistor Network for Proportional Voltage Output

My goal is to wire a BCD switch in a 5 volt system and get a voltage proportional to the 0-9 on the switch. My first thought was BCD -> R/2R network. That does not work because the R/2R network expects its inputs to be Vdd or Ground. The BCD switches produce short-to-common or open-circuit. Some solutions have occurred to me:

1. 
   

   Use a digital buffer with pull-ups between the BCD switch and the R/2R network. The 74ALC746 can do this but it seems unlikely that I will find one in stock.

   
   



2. 
   

   Use a BCD switch with both complement and non-complemented outputs. Those are expensive switches!

   
   


3. 
   

   Use an R/2R/4R/8R network and a constant current source. Are there R/2R/4R/8R resistor networks? This seems to be less energy efficient than #1.

   
   


4. 
   

   Use a microcontroller. That will work but a simple, purely hardware approach is preferred.

   
   

Do you have any suggestions?

Thank you