Sounds pretty much the same as futanari (dick girls). As you say yourself, a clit developed to be large pretty much is a penis. There's tons of erotica of that. Women using strap-ons on each other are also pretty common.
I was wondering why I was having trouble getting inspired to continue an erotic story I've been working on. Then I noticed my shampoo bottle said: "Herbal Essences Drama Clean: I'm so good I'll put clean thoughts in your head!" And I thought well, clearly I need to get some new shampoo if this one's washing away all my nice dirty thoughts!