You can do a What's New type search. You can set this type of search for just video, or just music, etc.

Having a browser would mean it would need to be hosted somewhere. Since there is no gnutella client program that "owns" the gnutella network, then who should list it. Particularly since it could contain copyright files which in many countries is illegal. Not a practical idea. You can use bitzi to help you find what's available (however not all those files are on the gnutella network & not all are listed.)