Designing Analog Chips

There is an awesome book on designing analog chips available for free over at http://www.designinganalogchips.com/_count/designinganalogchips.pdf .  This was written by Hans Camenzind best known for inventing the 555 timer chip.

Tube Chips

What if vacuum tubes had progressed in the same direction as integrated circuits?  Becoming smaller and more integrated.  Would it be possible to build an integrated vacuum tube circuit with hundreds or thousands of tiny vacuum tubes built into a chip like circuit?  Would there be an advantage to doing this?

Update: Korg musical instruments has developed a vacuum tube oscillator using a method similar to what I describe here.  It is called a nutube and you can get one in the Nubass synthesizer.