Has "GHz-spinning dust" ever been demonstrated in the laboratory?
This poster suggests an answer of yes and no. Essentially the poster reports a demonstration of some of the proposed mechanisms, but the rotation speeds produced are in the $kHz$ not $GHz$ range because the dust partcles are bigger, the vacuum less good and so on.

To quote the summary:


  
  First laboratory measurements of rotation of the analogs of interstellar
  dust grains induced by radiative torques have been made
  The measurements were made on irregularly shaped SiC particles
  particles of ~ 0.17 to 8.2 $\mu m$ effective radii levitated in an electrodynamic
  balance and illuminated with laser light at a wavelength of 5320 Å, at
  pressures of $10^{-3}$ to $10^{-5}$ torr.
  The rotation rates with radiation intensities of ~ $4-30 Wcm^{-2}$ were
  observed in the range of 1,000-22,000 rot/sec.
  The grain rotation rates were observed to follow the expected functional
  relationships, being directly proportional to the incident radiation
  intensities and inversely proportional to the drag represented by the
  ambient pressure.