Not totally sure what you plan.
To address a vid from YouTube does of course require the usual code per your example url - and I don't think a url using an .flv filename will work. So - wondering quite why you want the .flv name.
If I download a YouTube vid with my download manager then of course I will finish up with an .flv with a filename.
Maybe you can explain a bit more what you are trying to do and why.
Of course some programs exist where you put in the youtube video url, it then contacts the server and gives you the .flv link in which you can download. I have researched this and youtube of course use many servers, therefore there is no static url which you could use, as an example: flv.youtube.com/kfjf76f-O, of course it would be more like:
server1.youtube.com/kfjf76f-O.flv
server2.youtube.com/kfjf76f-O.flv
I was simply wondering if anybody knows how you would create either a website or exe that would find the .flv link, a good example is
www.mediaconverter.org.
Thanks for your time.