Audio should be able to stream without frequency limitations, but finding a music source that streams at a higher frequency will be the trick. Besides frequency issues, streaming music is usually done so with compression. Again, finding good quality uncompressed streaming music may be a challenge. I know that on iTunes, I can choose a higher frequency for downloads, and I can choose to Download files as AIFF instead of mp3, so my music sounds pretty good, but it doesn't come close to the sound of DVD Audio discs.
I'm thinking of dumping my KEF speakers and high-end audio equipment (and extensive CD collection) if I can get the same kind of frequency response using digital streaming (from the internet) and some high-quality headphones. Will this satisfy my needs?