I'm thinking that at least some turbocharged engine users would like to use
non-electric (vacuum) gyros as a backup for their fancy glass panels.  I
have a design (patented, in fact) that allows a turbocharged engine to
supply the required differential pressure to vacuum instruments under all
operating conditions without the necessity of a vacuum pump.  This could
also be used to supply the primary flight instruments, but perhaps some
people would be reluctant to go that far.  For a backup source it would be
ideal as it is lighter than a vacuum pump and has no wear parts.  I
personally like the idea of using vacuum gyros as a backup as they have no
electrical requirement at all - potentially eliminating the need for a
redundant electrical system in a glass-panel plane.  The device is basically
a pressure regulator that automatically selects pressure from 3 or 4 sources
and picks the appropriate pair of sources to produce the required
differential pressure.  It picks from the intake manifold, compressor
discharge, atmospheric and cabin pressure(in the case of a pressurized
aircraft).  It starts from the lowest and picks whichever supply is
necessary to get the appropriate pressure.

Any interest?  Comments?