Looks like the first phoenix number seems to be the correct one: 1803714 (Plug - MC 1,5/16-ST-3,81 - 1803714)
You can try to find stock (single pieces) via findchips.com. http://www.findchips.com/search/1803714
But then it appears the NI package is cheaper and you get some label cards as well.
If you like to have PCB mountable option you can use 1875564.
In my case (I would like to make a simple test system using the board) the better option seems to be the OEM version. NI USB-6009 OEM (or 6008 OEM). This can be mounted directly on a PCB using some simple standoffs and a cheap PCB connector. The type mentioned in the datasheet is an old, non-rohs compatible one but a new one is the 8534-4500PL which you can buy at any streetcorner.. (Digikey MSPV34-ND is new one, 8534-4500JL-ND is old one, Digikey niceley presents the alternative). http://www.findchips.com/search/8534-4500PL gives a list of all streetcorners...
