Vacuum Tubes!

A colleague of mine told me that good old 6550 power audio tubes are
selling for a ton of money! This got me to thinking about "Virtual Valves"
or "Perma-Tubes". The idea is to build HV mosfets into the base of a
standard power pentode pin-out. Give 'em the same V-I curves and viola!
You have "tube sound" that doesn't wear out and can actually be used in
your old Fender and Marshall amplifiers! If I produce such a product I'll
use the name Virtual Valve, Perma-Valve or Perma-Tube whichever I can register.
-CDT