More than three nested parametric sweeps in LTspice
I managed to do it using the TABLE function for each of the five variables. The problem was that the size of the tables (given by the number of total parameter combinations) was prohibitive to write by hand. So I wrote a C++ script to create the tables as (long) text files. Then you use .include and .step param and the TABLE function in LTspice to perform the sweeps. The probe cursor indicates which 'key' (i.e. parameter combination) was used for each simulation. The general idea (not the implementation) came from the LTspice yahoo group (e.g. https://groups.io/g/LTspice/topic/50201465#60860).