This whole iTunes for Office swap that everyone is speculating on does not mean much.
Apple gets zero benefit from working on an iTunes for Windows 8 touch devices - there is insignificant marketshare for these devices, so Apple gains almost nothing from offering the product on Windows 8 touch. If this was just a case of recompiling the existing iTunes code to ARM, it would probably make sense, but Apple needs to do a lot more than that.
For MS however, not offering Office on the iPad is a massive blunder. iPad is a very significant product, and by not offering Office for iPad, MS risks that there will be tens of millions of users who use the iWork products - simply because there is no other option. At some point, if there is a critical mass around iWork, that could actually be a costly problem for MS. The difference between iWork and Office is not so much about usability, functionality, performance or anything like that. It is quite simply the fact that everyone has Office, and very few people have iWork. So if you create a doc in iWork, and send it to someone, there is a big risk that the recipient might not be able to view it, because she doesn't have iWork.
And of course, there is the small matter of missing out on approximately $50 of revenue from literally 10's of millions of tablets!