The list I ran when I first switched to mech - 58 points
Canoness with bolter, krak grenades
4x 10 Sisters, flamer, heavy flamer, Vet with combi-flamer & book, rhino with extra armour
4x 4 Celestians, 2 meltas, immolator with extra armour
3x Exorcist tank
(it was a few years back so the list is probably a little off, but close enough)
Assault 0, Shooting 24, Missions 18, Misc 16. Could probably claim another 4 points for 'special rule that significantly helps them stay alive' with faith.