  The BL Lac object S5 0716+71 was observed in a global multi-frequency
campaign to search for rapid and correlated flux density variability and
signatures of an inverse-Compton (IC) catastrophe during the states of extreme
apparent brightness temperatures. The observing campaign involved simultaneous
monitoring at radio to IR/optical wavelengths centered around a 500-ks INTEGRAL
pointing (November 10-17, 2003). We present the combined analysis and results
of the cm- to sub-mm observations including a detailed study of the inter- to
intra-day variability and spectral characteristics of 0716+714. We further
constrain the variability brightness temperatures (T_B) and Doppler factors
(delta) comparing the radio-bands with the hard X-ray emission (3-200 keV).
0716+714 was in an exceptionally high state (outburst) and different (slower)
phase of short-term variability. The flux density variability in the cm- to
mm-bands is dominated by a correlated, ~4 day time scale amplitude increase of
up to ~35% systematically more pronounced towards shorter wavelengths. This
contradicts expectations from standard interstellar scintillation (ISS) and
suggests a source-intrinsic origin of the variability. The derived lower limits
to T_B exceed the 10^12 K IC-limit by up to 3-4 orders of magnitude. Assuming
relativistic boosting, we obtain robust and self-consistent lower limits of
delta >= 5-33, in good agreement with delta_VLBI obtained from VLBI studies and
the IC-Doppler factors delta_IC > 14-16 obtained from the INTEGRAL data. Since
a strong contribution from ISS can be excluded and a simultaneous IC
catastrophe was not observed, we conclude that relativistic Doppler boosting
naturally explains the apparent violation of the theoretical limits within
standard synchrotron-self-Compton (SSC) jet models of AGN.
