Apple has generally had a policy of not helping merge accounts (way back to the iTools days), in line with overall policy of being much more ruthless in end-of-lifeing stuff.
But Tim Cook implied in an email that they are looking for a solution (mainly about merging MobileMe into Apple ID I think). I suspect something will turn up as MobileMe nears EOL.
Either way, Apple does not announce things before they are ready to ship (the sole exception being the original iPhone 'cos FCC approval as needed).