Well it's not a rare ship per se. It has a steady fanbase and decent amounts of fanart. I just think it's a little too straightforward and bland for Touhou.
Not rare for sure, but not something you see tons of either. I have several works of ke-ta The art is beyond amazing.
Sanae I usally love to see with Aya or Kogasa.
Anyone who' been on Danbooru should have seen mizuki hitoshi's self insert with kogasa and Sanae. Great daily comic.
@victim
There is actually a book called Ammonite wherein a woman ends up on another world where humans evolved separately for thousands of years, all women, without men, reproducing in a... vaguely similar fashion as to what you describe x3