This is not cool yet, but might be with some clean up.
There are frequently questions in the forum about multi-level validation (changing an entry in one drop-down list causes the validation for downstream drop-downs to change). The attachment illustrates an approach that might be refined to do this conveniently. Changing A1 changes the validation for B1; and changing B1 changes validation for C1. It could be extended as deeply as desired.
One enhancement would be to automatically generate the validation formulas in A2:C2, and the validation table in A3:C36 with a macro.
Suggestions invited and welcome.