Certainly, it could be taken as far as those adorable little pocket creatures. But I kind of conceive of it as a way of generating some more socializing/sharing of music. And of course, it would be totally contingent upon how much "back ground" resources were available, etc.
The whole idea, I guess, though would be to pick your favorite song for the month. Since the "genetically enhanced" songs would be completely random, you would have just a good a chance of picking one of the uber-pets as anyone else.
So, say I am a HUGE Hanson fan...just can't get enough of the MMM-Bop song. (Trust me, this is a hypothetical) and say, you are a huge Crash Test Dummies fan, and you love that MMMMMmmmmMMMM thing they do.
Now. Somewhere in the background, the "game gods" have decided for the month of MMMMay, these Pet Sounds (could have gone with the Beach Boys for this as well, I guess) will be the genetically enhanced songs that produce a superb union.
You and I happen to decide to share our "pets." We WIN! Our prize? An exclusive pet icon that we can put on our Zunetags (XBox Live as well). You get to keep that tag forever.
If you wanted to, you could extend the "mating" a bit more, vis a vis the scavenger hunt scenario...our MMMM-Bop/ MMMmmmMMM union produced a new "pet" for each of us. It's not really a song anymore...but, I find some else to share with...a big Cyndi Lauper fan...my MMM-Bop+yourMMMMMmmmm+her She-Bop now produces a super-huge-wonderfully brash even cooler than before super-breed MMMM-Bop-mmmMMM-SheBop pet icon.
Which is also why you don't want people changing their pet songs too often during the 28 day cycle. Once word gets out that a couple of these combinations "unlocks" your forum "icon," "coin," "badge" or whatever, you don't want everyone to be able claim best of breed for that month.
Also: the behind the scenes breeding officials, asthey are known, could "tip" the potential pet owners off as to "themes" they are looking for if they wanted to narrow the "gene" pool a bit. October: Halloween...Cranberries--Zombie+Eels--My Beloved Monster+Monster Magnet--Spacelord+etc. etc.=that month's unlockable superpet breeders' award. Each person can only start with one pet, so they would be forced to network a bit to find another person whose pet might fit the right formula.
So...uh, yeah...it's like Tamagotchi.