I think your idea has merit.
There is a wealthy individual somewhere who started this "God" billboard campaign, and they are all over the nation in various places, black background with white letters, with sayings like "I meant the part about Thou Shall Not", and so on. It is non-specific to any denomination, or even Christianity. It just espouses Judeo-Christian values and does it in a way as if it were being spoken by God himself.
I've also seen them by some organization with thoughts like "Character", "Perseverance", and using Abe Lincoln's history of failure before his success to illustrate the concept.
I think key to this *might* be to enlist the participation of certain 'freedom loving' organizations (start with all our RKBA orgs-- NRA, GOA, 2nd Am Sisters, JPFO and so on). Branch out to various others. One or more may choose to underwrite it entirely, or provide financial participation.
I'm a bit pressed for time, but will think about this as the day goes by and maybe post more later.