It seems the answer is yes: From
-> Frequently Asked Questions -> see the 3rd item
it looks like the old fashioned technique will still work to at least to get apps from multiple Apple IDs onto a device. Not sure if it will still work for downloading updates to them. I'm guessing yes.
I read all the responses and was myself trying am living in Germany, but my main Apple ID is from Canada because thats where I come from. I tried to download an app that I could only find in the German store, it downloaded fine, but then when I tried to sync the app to my iphone, it wouldnt even start syncing before coming up with an error. I personally dont mind about doing manually, but I just dont know how to get started.
Ran into a problem where apps on iphone were asking for passwords for differnt iTunes Store accounts in order to update the app.
The user has a me.com account now.
1. We had logout of the Store account in the setting and login with new me.com address.
2. delete any apps on the iphone that request the password for the old iTunes account.
3. Reinstalled the app from the store, it will install using the new me.com account.
4. Update all will finally work for the apps that were installed under the new me.com account.