I was curious about this - as I read it, Master Spellthief + Godsblood Spelltheft = Domain Casting, limited only by CHA modifier.
You steal a spell from yourself (which you can do, since you can steal from friendly casters), convert it to a domain spell, and cast it. It doesn't reference your spellthief spellcasting ability anywhere, so I can only assume the level of spell cast is only limited by the level of spell stolen.
Am I reading this right?
Also, I assume the spell is cast using Cha as the spellcasting stat, but is there anything to support that? Why couldn't it be cast using Int? Or, for that matter, Wis?