have found a house I LOVE online unfortunately I am not in the position where I can buy I don't know of this is a crazy idea but maybe I should write a letter to the landlord and post it in the property asking if it would be possible for me to rent?

I would check to see how long it has been on the market before doing that. If it is a new listing, they will most likely turn you down as it hasn't had a chance to sell. If it has been on the market for over 6 months, go for it. They might be itchi g to move and this can help them.