Why since the late 60's we stopped looking at things like this. With today's technology you could make some pretty cool versions of this.
I honestly had a similar question while I was at a turbine course for Solar Turbines. In a remote mounted application, why couldn't a more efficient axial flow turbo be used instead of the more simple compact centrifugal turbos we all are so fixed on?
Ive never heard of them so I googled it, sounds interesting
http://www.tunersgroup.com/tunerwire_live/turbonique.html