First off don't you think if such a spell was out there that there would be more rich witches? Second, if there were such a spell do you honestly think it would be shared? Thirdly, dont you think that is a rather greedy way to use magic?
You cannot become a dragon in the physical realm, dorianh. You are human and you always will be.
As for the main topic, I highly doubt that that is possible as well. You can't just stare at the ground and have gold shoot up at you, no matter what spirits you invoke. You could perform a ritual to help you get money though, but it won't just appear in front of you.