Slow rotor,
my numbers for the Djinn are an airflow of 1.1Kgs/sec.
A turbocharger like the garrett GT40 can provide 1kg/sec at 2.5 bars. Another example is the ROTREX superchargers, the bigger can provide 0.8 Kg at 2 bars, i asked their eng team and they estimate the power required to run 2 units at about 75 Kw.
BUT using cold jets for prerotation is different than for main power source. The airmass needed is far less since you don't power the rotor with it. BTW, for a gyro, the rotor doesn't acts at high AoA.
According to rough calculus,i have estimated that i can get 25 lb of thrust on each blade.
You can't compete with a gas turbine but the Artouste and Palouste are old generation turbines.
talking about RC turbines, i believe there's something to do, check this link :
http://www.microjeteng.com/prop.html
but the price must be pretty high.
Thanks
Victor