Even then, as with "Passion," there are limits. Mel found he had to go around the traditional Hollywood marketing venues to sell the picture. I'm sure our "Malta" will have to be sold the same way, through churches.
I thought Gran Torino was a stunning movie. At the end I was speechless and didn't want to move.
Last year I stumbled onto an interesting historical film about King Arthur on CBN called "Pendragon: Sword of His Father" by Burns Family Films. It seems they share somewhat the same mission as you about making films with a respectful treatment of the Christian influences on history.
Don't know how you're fixed for actors and production resources, but perhaps they might be of help.