Jazz notation practices could pretty easily be adapted to this.

The effects of notation are paradoxical -- on the one hand, you can notate what had previously been transmitted by ear and essentially freeze a tradition from further development(which is what happened to German folk music, and was similar the practice in many East Block countries); on the other hand, the development of a tradition of informed but creative _reading_ (and mis-reading) of musical notation is potentially very rich. (The composer Richard K. Winslow put it this way: "if you want music to be played exactly the same, transmit it orally; if you want it to change over time, write it down).

A bit of writing and reading might do rock well. I believe that sufficient notational devices already exist, and it's telling, to my ears at least, that the least-notated part of the rock practice, the percussion, is precisely the area of the ensemble that has become most stagnant in recent years.

That's an interesting point, Daniel, and does shed some light on rock percussion as it is today.

In cases of acts like Sigur Ros, given that their compositions are so sound-specific, I'd guess that they wouldn't bear much fruit in more abstracted forms such as written instruction. Perhaps as meta-art or lateral thinking devices, but little beyond.