Officially, all Canonical has to say is "Our company policy is that we don't comment on any rumours that might be circulating. We'll of course keep you well informed of any news that comes out of Canonical." Away from public relations though I'm hearing that Canonical and IBM have working hard on expanding Ubuntu's reach on IBM hardware.
As for IBM? Linux has been very, very good for IBM over the last decade and they're getting to like Ubuntu. Historically, IBM has allied with Red Hat and Novell/SUSE. But, as IBM's VP of Open Systems Development, Dan Frye told me recently, IBM is operating system and Linux agnostic. IBM will support what its customers want, and so, it appears to me, that IBM's customers must now be asking for Ubuntu. Sometime soon it looks like they'll be getting it.