Ideal SPICE Model of Op-Amp with Power
LTSpice offers the ability to make a VCVS with piecewise-linear transfer function:

Syntax: Exxx n+ n- nc+ nc- table=(, , ...)
A look-up table is used to specify the transfer function. The table is a list of pairs of numbers. The second value of the pair is the output voltage when the control voltage is equal to the first value of that pair. The output is linearly interpolated when the control voltage is between specified points. If the control voltage is beyond the range of the look-up table, the output voltage is extrapolated as a constant voltage of the last point of the look-up table.

(source: LTSpice help file)
With this you could make a transfer function with linear characteristic for \$-V_s/A &lt; V_{in} &lt; V_s/A\$, and fixed output at the supply rails (or whatever limits you think best model your op-amp) outside those bounds.
Other SPICEs likely offer similar capabilities.