MobileMe "email only account" on iCloud?

Question

OK, I've converted my MobileMe account on my laptop and iPhone to iCloud. Am already enjoying the PhotoStream feature! My question: We have an iMac running Lion at home, and my wife uses it as her primary computer. Under MobileMe we've had an "email only account" we're paying extra for. We want to keep her separate email account on the iMac and eventually be able to sync it through iCloud with her iPad when she gets one for Christmas, BUT we want everything else on the iMac - photos, Contacts, Calendars, etc. - to sync with MY iCloud account. How do we accomplish this?
Until we can figure this out, we're leaving the iMac alone and not converting it to iCloud. Thanks in advance for any answers!

Answer 1

Thanks, that was a helpful response! I think we did pretty much the same thing you suggested.
The issue: MobileMe account including its own email account on one computer, with the user also paying $10 for a second email-only account on another computer. The MobileMe account is used for joint Contacts, Calendar, and Safari Bookmarks on two machines, while the main MobileMe mail account was used for mail on one machine and the email-only account was used for mail on the other machine.
We wanted to upgrade to iCloud on both machines and still have joint Contacts, Calendar and Safari bookmarks, plus share our iTunes account and use the new PhotoStream feature on both machines - but preserve the two individual email accounts.
Solution: On the first machine, move to iCloud with everything, using the main MobileMe account name and password. On the second machine, USE THE EMAIL-ONLY ACCOUNT to create a new iCloud account using the username and password for the email only account. That appears to be the critical step: you need to create that new iCloud account with the username and password for the email only account FIRST rather than migrating to iCloud on the second machine using the main MobileMe account name, or else you may permanently lose that second email-only account!
After that, it's all a matter of tweaking the account settings on the other apps to direct to the iCloud account on the first machine.
You will get a screen asking if you want to delete the existing Contacts on that second machine. Do so: DELETE THE EXISTING CONTACTS on that second machine. (Only after backing up your Address Book by using the export function just to be safe.)
Then, WITHIN EACH APPLICATION - Address Book, iTunes, Calendar, Safari - go to the Preferences and set them so that they are tied to the iCloud account for the first machine.
You may need to check your Preferences: for a little while my wife was getting both my mail and hers, until I noticed that within Mail.app she had two accounts: her iCloud account AND my iCloud account. I deleted my account on her machine.