Static Site Generator for prototype

Question

I have been reading a lot of information about using Static Site Generators (SSG) for prototyping. The problem is that there seems to be an ton of options and I do not have time to test that many of them. I'm familiar with HTML, CSS, LESS and some PHP - and I would love not to dive too deeply to coding.

I am mostly interested in having templates for segments of HTML-code, prettier-than-PHP logic for showing them and handling of navigation. And simulating dynamic content by using custom variables to insert text into HTML templates.

Stephen Hay advocates Dexy in http://www.amazon.com/Responsive-Design-Workflow-Stephen-Hay which seems nice for it's documenting features. However documenting is only an nice-to-have feature for us. Also Dexy does not, to my understanding, watch for changes and offer live generation of content but needs to be constantly rebuilt.

Jekyl, Nanoc, Phrozn, PieCrust and Stacey, for example, seem nice choices. Mixture is an option also.

My question is which SSG would make it easy to have multiple navigation levels, like this...

Home
 |
 |- Group 1
 |   |
 |   |-section 1
 |   |-section 2
 |   |-section 3
 |   
 |- Group 2
 |   |
etc. etc.

...and simulate dynamic content by easily inserting variables from separate text / markdown etc. files into html / template language templates. If possible also from subpages, for example to create this kind of custom navigation:

 ––––––––––––––––––––   ––––––––––––––––––––   ––––––––––––––––––––   
| section 1          | | section 2          | | section            |   
| –––––––––––––––––––| | –––––––––––––––––––| | –––––––––––––––––––| 
||image from subpage|| ||image from subpage|| ||image from subpage|| 
||(custom variable) || ||(custom variable) || ||(custom variable) ||
||                  || ||                  || ||                  || 
||                  || ||                  || ||                  || 
||                  || ||                  || ||                  || 
||                  || ||                  || ||                  || 
| ––––––––––––––––––|| | ––––––––––––––––––|| | ––––––––––––––––––|| 
| text from subpages | | text from subpages | | text from subpages |
| custom variable    | | custom variable    | | custom variable    | 
|                    | |                    | |                    | 
 ––––––––––––––––––––   ––––––––––––––––––––   –––––––––––––––––––– 

I could of course use some simple cms, php includes and custom fields on cms pages but that would be quite slow to edit.