Is quantum tunneling in transistors patterned?
Something very like this is already in use. All transistors generate noise, from a number of effects: http://www.nikhef.nl/~jds/vlsi/noise/sansen.pdf

Intel have a hardware random number generator that uses this: http://electronicdesign.com/learning-resources/understanding-intels-ivy-bridge-random-number-generator


  The core of Ivy Bridge's ES is an RS-NOR latch with the set and reset
  inputs wired together (red). When the R/S input is de-asserted, the
  latch becomes metastable, and its output eventually settles to 0 or 1,
  depending on thermal noise.


It's still quite hard to eliminate various side-channels and effects of temperature and manufacturing variation, but that article gives a well-sourced discussion of why it's believed to be a good random number source.