I have a winphone 7.5, and my main Microsoft account uses my domain name, not a microsoft domain such as hotmail or outlook.com When I set up my phone I was under the impression that I couldn't use that (because I couldn't set up my corporate email client then which is the same address as my microsoft account), so I created a hotmail account just for the phone. That's a pain now, since I want to use my common onedrive, instead of a secondary onedrive. Alternatively can I use a different onedrive account than the one that's with the phone's microsoft account?
You need to use a Microsoft account on your phone if you want to have the "cloud magic" happen. The Microsoft account can use your corporate email address (actually I have an Microsoft account that uses my employers domain name as a second one for my corporate phone).
But: this account then has nothing to do with your active directory account. It is still a Microsoft account. You can, though, add a second mail account to your phone once it is set up.
If you've created a Microsoft account using your corprate mail address, you might ask Microsoft to merge them (at least I think you can't do this on your own). This way your two accounts could be consolidated.
The next paragraph is less a technical point of view than an organizational one:
But: if it's a private phone, it might be a good idea to have a line of separation. You need to reset your phone to have the new account linked to the phone. Unless those accounts are merged, all purchased apps are not available (purchases are linked to the Microsoft account used for purchasing). Anyhow, if you leave your company and have mixed purchases (some personal, some work), then you're kind of screwed up unless your current eomplyer allows you to use the apps he paid for even when your contract has ended.