Official Ubuntu Rolling Release Proposal

A while back, Leann Ogasawara, Canonical Kernel Team Manager, has said that it has been discussed internally to use a rolling release model for Ubuntu between LTS releases, but that it is just an idea for now. With the new Ubuntu Touch, which needs both "velocity and agility", the rolling release mode seems to be more than just an idea and Rick Spencer, Engineering Director at Canonical, has made a proposal about this on the Ubuntu Devel mailing list.
In the thread named "Let's Discuss Interim Releases (and a Rolling Release)", he states that "we should keep LTS releases, but starting now, stop doing interim releases and start a rolling release".