This super/turbocharging idea isn't new.  Here's a link to some shots
of the Finnish treatment done to a Mercedes OM617 diesel engine: 
http://www.kolumbus.fi/valtonen.motorsport/index.htm
That guy's doing it solely for the dragstrip.

Also, both Opel and BMW have twin turbo diesel engines in production
that utilize a small housing turbo for low speed spool-up, then kick
in the larger housing unit for mid and upper range powah.  These are
exciting times for diesel engine technology.  Gasolene sucks.

Casey
Olympia, WA
Biodiesel:
'87 300TD intercooler (209k)
'84 300D (204k)
Gashuffer:
'89 Vanagon Wolfsburg Edition (185K)