Digikey doesn"t sell that Model of Condenser Element anymore as Panasonic Has Discontinued that Model but you can get Elements with just as Good Or better frequency Responce at :
http://www.jlielectronics.com/spec.htm
I just ordered 20 Condenser elements from there, I got 10 of one Kind and an assortment of others so I can try to find the Best ones for certain uses.....
I actually might put some of the parts Together as Kits and sell them on e-bay....
You can get the Capacitors and Resostors at any electronix Supply store Like Radio Shack, I got all of the Caps and Resistors too make 2 Mics for under $2 but I am going to Make some Basic Circuit Boards to wire them together as it will be neater and Smaller and less problematic....
You can get the Male XLR Connectors at Most Music Stores or even on e-bay..
I think I am going to just use metal Tubes for the Body of my Mics and Put mesh over the end you sing into , also you don"t need to use a 9v Battery either as the Element only needs about 3v-5v to Run so I use 2 or 3 small watch Batteries that I get for 0.25c each at the Dollar Store....
They are Pretty easy to make but if you need any help just let me know....
Cheers