I FOUND A SOLUTION! At least to the 2 id's, one for the store and one for Mobile me mail accounts. What you do is use the store a/c for your "Primary" iCloud settings, which for me is an AOL a/c that I used to set up one iCloud account, and historically used for all purchases. Then use the mobile me account, also used to set up a different iCloud account, to set up a secondary iCloud account setting in all your devices that will only do mail for the me.com address. This can be done. Use the iCloud button to set up the Primary, and the separate mail, contacts, etc. button to set up the me.com iCloud account.
Before I changed all my devices (iPad, iPhone, MacPro, and PC) to the primary iCloud account I saved my iCal settings because they will all go away with this change. I also saved my contacts in an importable setting, but this was not necessary, as the contacts do not go away. I had to edit the future calendar items to point to the cloud, to sync with other devices, but the history is intact in iCal. I also added the mobile me mail account separately on the iPad and iPhone after the change.
This does not help if you have multiple store accounts, but at least you can have the store ID be on point for photo streaming, document sync, etc, (which will never work if you don't have the store Apple ID on every device as the main iCloud) and you can save your Mobile me mail account.
There is an Apple article on "Secondary iCloud accounts" that describes this in more detail.