Interesting idea.
If QSpice and provide a behavioral inductor, it could do the same for a behavioral capacitor.
Question: How often in real-life does the inductance value (or capacitance value) change in the middle of a sim? Although the same could be said of a resistor, there are reasons for a behavioral resistor for implementing a potentiometer or source resistance from power supplies that change on load or temperature.
If your goal is to run multiple simulation runs with different values of inductance, you can already do this by stepping a parameter assigned to the inductance value of the inductor.
The same is true for caps as well.
Len