What this thread is not: Yet another thread to argue about the balance issues of the Summoner class or tell us how you hate the class. There are plenty of threads for that.
What it is A thread to give examples of fictional characters that could provide good origin stories for Eidolons, perhaps with some reininterpretation because, gee not all fiction is structured with Pathfinder rules in mind. If it touches on an argument about summoners, feel free to mention it, but only in passing.
Stitch--Lilo and Stitch, dangerous, comes from another planet but it would work as another dimension. Also good example of the "imaginarry friend" of a child summoner which isn't so imaginary and a good example to bring up as a counter argument to the idea that an inexperinced (low level) character can't have an eidolon.
Other Dimensional Magical Girlfriends--Two come to mind. Jeanie from I dream of Jeannie and Belldandy from the Manga/Anime Oh My Goddess. Both are supernatural and come from out there. There is tension with the human. Both but Belldandy in particular would have an archtype increasing mental stats probably at the cost of physical stats which Paizo has not given us (but should). While both too powerful for the standard Eidolon, they could be inspiration for an eidolon.
R2D2--Could be a good model for an Eidolon. Very Loyal to master Luke. Skill monkey rather than combat monster. Literally falls from another world.
Hope this is interesting.