This is the only doujinshika I've seen so far whose work is quite definetely SnapexHermione. She's done two books and one copybon, all with Snape and Hermione as the main characters, although the stories are light and innocent. I think she's done doujinshi for some other series as well, or so her site indicates, but I've never seen them. Her artstyle isn't to my usual taste, since I like things sleek and cool, but it is in a way quite sweet, and Hermione in particular is depicted as exuberant while at the same time being shy. Her stories have a definite SuneHa- slant, although Ron is also fond of Hermione.

Sale/Trade Willing

Title : Otomegokoro to Aki no Sora (It's Impossible to Understand a Girl's Heart) Published : 17/Mar/2002 Size : B5 Comments : This book is mainly gag with very soft and light hints towards character interactions. The first story has Snape annoyed with Lockhart and quite abusive towards one of his books because Hermione thinks the new DADA teacher is talented and clever instead of, as we know him to be, a huge fraud. [28 pgs]

Himitsuya's website:

The Harry Potter section of her site has disappeared,
but the Snape&Hermione Union remains,
if you know where to find it.