There are simply many small bathroom floor plans you can adopt. It all depends on size of bathroom that you want in relation to number of family members and size of your house.
Ranch style homes have just enjoyed a come-back. People who want very cozy single story ranch or rambler home usually like to see different open floor plans. These plans make it easy for them to design their own home in the perfect western style.
You might want to review some small apartment floor plans with one bedroom as you are considering constructing one on a small budget without wasting more time on where your bedroom should be.