You could use a parameter sweep for the inductance value.
Then you would get results depending on 2 variables (frequency and inductance value).
Most of the data would be useless, as it has not the frequency-inductance relation, that you want.
With a little octave postprocessing you could then extract the data you want.
You could write a S-Parameter file (containing the changing inductor) and insert that in your schematic.
I guess you would have to calculate the values for the S-Parameter file in a spread sheet,
as qucs cannot export touchstone files.
Have you looked through the qucs documentation ("Tutorial - Getting Started", "Workbook", "Technical paper")