What's an SSG? I've gone and tried to look it up on wikipedia, but there's nothing that appears to be relevant.
> In a wiki the data is usually
> laid out hierarchically.
What? No. In a wiki the pages are semi-automatically linked. Go and look at the very original wiki, the very first one by Ward Cunningham[0]. Pages are linked completely according to the text, and there is absolutely no hierarchical structure. Even wikipedia has no hierarchical structure because of being a wiki. It has some structure, but that is imposed independently.
You then also say:
> ... not using a browser ...
So it would appear that we have established that what you want:
* Isn't editable through a web interface - unlike a wiki
* Has some sort of hierarchical structure - unlike a wiki
* Doesn't use a browser - unlike a wiki
So what you want is, in fact, not a wiki. That leads me to wonder what you do actually want. You seem to want to have some pages that use markdown (or something), and are somehow arranged in a hierarchical manner, and then somehow presented in that hierarchical manner, but without using a browser.
So I don't understand what you want. Here are some questions:
* You say you want the files in some sort of hierarchy - how is that defined?
* How do you envisage a user accessing this static "site" given that you said you don't use a browser?
* After you make a change to a page, do you initiate the re-building of your static site manually, or do you envisage some sort of automated process?
* Where is your "simple static wiki" stored, in order to be accessible?
* Is it just you accessing it? Or is it open to others?
Answers to these (and many other) questions might help us understand what you actually want.
Just don't call it a wiki.
[0] http://c2.com/cgi/wiki?WelcomeVisitors