Having them be enchanted regular items is a fun idea, but might add a bit too many limitations for what you can actually have as the items, and might feel out-of-place if you get too creative with it. Like, (if you didn't want it to be penetratable) I could see a pussy being represented by a fruit, if you've ever seen those sorts of images, but I feel like that would absolutely be weird to just be playing with a fruit. But it could definitely be done for some items, I just don't think you need it to be a hard-and-fast rule.
Yeah, I do totally get what you mean about wanting it to focus on seethrough clothing and whatnot. I'm just saying what I like in games, feel free to disregard as many of my suggestions as you'd like.
I am curious, what is that idea that you're thinking about with regards to the shopkeep? Or is that too much of a spoiler?