Looking for docs on "A" RR duality of functions

Hi. Do you know if there are any docs (RFC, drafts, independent...) that study the tricks being done with the A/AAAA RRs? What I mean is that it is currently being used not only to resolve the IP address of a hostname, but for load-balancing as well, the case being that the hostname is not just a "host"-name anymore, but a "service"-name (?) so to speak. I'd like to know if somebody else has gone deeper into this and if there are related documents on the matter. Thanks.