i would be all for it, im sure alot of you have used virtual dj programs, and have the experiance to dj.
as for the genere issue, i belive it should be up to the performing dj, since having 10 different channels for different genres would take 10 djs at the least. and since it appers that there are alot of people willing to dj, the music genre would probably change evey hour or so.
ive used shoutcast, it works flawlessly, can hold alot of people, and best of all, it works with winamp =D
ive also used vdj, i had alot of hassle setting up the broadcast feature though.