Suggestion for Proof of Concept PbP game

[Helaman]

I am looking to run a test bed for a stack of house rules which includes E6/E7 play and is low powered. It also includes some horror themed component of house rules.

This is not a recruitmnt thread... I am after some advice.

Looking for module ideas (don't want an AP) of what would (in your suggestion) be a good place to strt and why. The modules dont necessarily need to be back to back or same series.