I think in all the conversations about fictional incest I've ever had, there has been near-universal agreement that parent/child is squickier than sibcest. Sometimes in discussions where that's the only thing anyone can agree on at all. (Incest: people haz opinions!)

Veronica Mars Veronica/Keith is the pairing I've written, yes (wisdomeagle and I both wrote each other Keith/Veronica/Mac one year for 3_ships). Outside of Ari and me I don't know very many people who 'ship it (she converted me), but really once you have been converted it's so canon it's kinda painful.

Although I have sort of always wanted to write Hank/Dawn.