Ok I'm going for a second VCO. As the Z3000 is impossible to find for now, there are few modules I'm interested in. Analog, affordable and in stock. Any advice ?

WMD/SSF Spectrum
Richter Anti-Oscillator
Richter Oscillator II
Sputnik Modular Oscillator
The Harvestman Polivoks VCG
Analogue Systems RS-95e
Killpatrick K3021