I pulled together a rough proposal for representing binary data in ECMAScript and posted it on public-script-coord. I think having this is important for many W3C (and particularly WebApps WG) specs, but it is probably best defined in ECMAScript. I'm posting a link here in case anyone is interested and is not on the public-script-coord mailing list yet:
http://lists.w3.org/Archives/Public/public-script-coord/2009OctDec/0093.html Regards, Maciej
