If that's all you want then rip the spawn protection from MH2Gold and make your own simple one. It will do whatever overlay you want for any time period you like and that's all it does (no extra fluff).
The class "SpawnProt" is the mutator and "SpawnProtEffect" is the overlay. You can find a few setup lines in "MH2Base" that will show you how to activate it, and this can be included into the "SpawnProt" class and a stand-alone mutator easily made.
There's nothing like making it yourself, and I'll help you if you need it
