I am new to VS Code, but I read there are extensions that can create code from JSON and so on.
So i thought, maybe it would be possible to create a sitemap from an item file.
The Idea would be to select a bunch of item definitions or an entire item file and click create sitemap for this items.
Or the user creates an empty sitemap and selects insert sitemap from items in clip board.
Maybe someone can include such feature in the official extension.
Just an idea… 
There is Home Builder that will create both the Items and the Sitemap.
I don’t know if automatically building the sitemap from the Items will save much work since there will be no control over appearance, order, organization, etc. It seems to me that you would end up with a mess that will take as long to “fix” the way you want it to look as it would have taken to write it from scratch in the first place.
But if someone wants to pursue this, don’t use the .items files. Instead use the REST API to get all the Items, since Items can be defined in PaperUI as well.
I personally like the HomeBuilder approach as it lets you build up the whole home model including the structure of your sitemap and the Items all in one go.
@rlkoshak I’ve been looking around and I’m not sure if there is much discussion going on about Homebuilder. Indeed at the moment I’m not really up to speed with things like Habpanel etc. But I am interested in the conceptual model that Homebuilder could used to design.
I don’t know what discussion you are looking for. Hombuilder is an add-on. It’s coded. It exists. You can install it and use it.