Rainla, are you crazy? Yes. Or maybe. Or no.
Sorry, not enough data. You might be. What's your point? Some folks dig the crazy chicks.
Is your dream crazy? I had a dream once about waiting for the school bus wearing a bathrobe sitting in a reclining lawn chair while all the other kids in the neighborhood shot each other with water pistols. Was that crazy?
Your feelings and desires aren't crazy. You recognize that by society's standards they aren't practical, or you probably wouldn't have asked the question. You also have clued into the idea that society's standards need not always apply, or you wouldn't be here. Your exuberance does give the old-n-crusties a chance to mutter at you, so that was fun though.
That said, there are some very practical concerns with poly life. People love to judge others is one. Amusingly enough, fundamentalists are very keen on forgetting the "judge not others" directive. This can have real and painful consequences, especially with children involved.
More relevant to where you are now, understand that poly relationships are geometrically complicated. Vees are therefore easiest. Triads are harder. Quads harder still, and so on. Five people of mixed genders living together and sharing children is a lofty goal. Though you may have the dream in mind, start with the simple and build. Where you get to may be your dream, or you might find some other happy place. I for one am still building on my dream. I actually had a talk just last week with my mono where I spelled out exactly what I wanted using the term "dream." She's supportive and wanting to help that dream happen, but it took me a long time to find someone with her qualities so it didn't have to be just my dream.
I believe that as you get more years of experience you'll find more people who can share your dream. Right now I suspect that many of your peers have a lot of internalized mono-programming. It seems that as people mature, they shed some of that programming and some if the associated hang-ups. Your dream is a long-term project, but it gets easier over time.
Best of luck.