Hopefully some of you have already tried this method of navigation so I thought I'd put a question up here and save myself from re-inventing the wheel.

Using nested numbers the default menu structure in the left sidebar looks like this if the user is viewing the page "3.3. Page Title":

1. Page Title
2. Page Title
3. Page Title
3.1. Page Title
3.2. Page Title
3.3. Page Title
3.4. Page Title
4. Page Title

This can be extended out to more than levels:
1. Page Title
2. Page Title
3. Page Title
3.1. Page Title
3.2. Page Title
3.3. Page Title
3.3.1. Page Title
3.3.2. Page Title
3.3.3. Page Title
3.3.4. Page Title
3.4. Page Title
4. Page Title

The difficulty with this method is if you have a lot of options (we tend to have 8 children to each parent page) and a deep website structure (5 levels) the vertical size of the menu becomes quite baffling.

The menu display system I'd like to use follows:

3. Page Title
3.3. Page Title
3.3.1. Page Title
3.3.2. Page Title
3.3.3. Page Title
3.3.4. Page Title

So the menu only shows the following:

• The page
  
• The page's siblings
  
• The page's parent
  
• The page's grandparent
  
• The page's great-grandparent
  
• etc.

In essence this is similar to breadcrumbs except the page siblings are shown too.

Has anyone take this approach before? Any code examples would be greatly appreciated.

Cheers
Tama