Get your beloved to help you with ideas. You can work together on a couple of things:
1) Have her come up with pictures of the kinds of beds she likes
2) Roam the furniture stores and pick out beds or features she likes. Take digital photos if the stores will allow it. Might as well look at the dressers and other accessories too - that will be next.
From that point you might be able to come up with your own design or modify an existing plan. The next small challenge in bed-building is the means of attaching head and foot to the side rails. There are several approaches and hardware is available (Rockler comes to mind first - there are others.)
Designing this kind of stuff is almost as much fun as building it.
RonB