is the project "dead"? No nexus-specific changes in the last days.
Where can I get information like ambitions, roadmap?
For sure it's not dead but of course since the Ubuntu Touch Developer Preview came out the focus is clearly on that.
I spoke to one of the core developers and he told me that Ubuntu on Nexus 7 will be slowly migrated towards the "Ubuntu on Tablets" and "Ubuntu on Phones" and this might be part of the solution "switching to the PC interface when docked with a monitor and a keyboard".