The Ultimate Sidebar Navigation

Hi,

I am looking for someone to help me with the ultimate sidebar navigation. Here is the layout:

Top Level Page 1
Top Level Page 2
Top Level Page 3
Top Level Page 4
Top Level Page 5

Each of those pages can have as many as three levels of child pages below it. For example:

Top Level Page 1
– 2nd Level Page 1
– – 3rd Level Page 1
– – – 4th Level Page 1

I never want to show all the top level pages because those are already in my main navigation. Instead if I’m on Top Level Page 1 I want to show only one level down. For example when on Top Level Page 1:

Top Level Page 1
– 2nd Level Page 1
– 2nd Level Page 2
– 2nd Level Page 3

For every other layer deep I want to show the children and siblings of the current page and all the other ancestors of that page except for the very top level, and I also don’t want the siblings if they are part of a different tree. In the example below I don’t want to show the 4th level for 3rd Level Page 2. I need it to look like this if on the 4th level.

Top Level Page 1
– 2nd Level Page 1
– 2nd Level Page 2
– – 3rd Level Page 1
– – – 4th Level Page 1 (Current)
– – – 4th Level Page 2
– – – 4th Level Page 3
– – 3rd Level Page 2
– – 3rd Level Page 3
– 2nd Level Page 3

Or if I’m on the 3rd level:

Top Level Page 1
– 2nd Level Page 1
– 2nd Level Page 2
– – 3rd Level Page 1 (Current)
– – – 4th Level Page 1
– – – 4th Level Page 2
– – – 4th Level Page 3
– – 3rd Level Page 2
– – 3rd Level Page 3
– 2nd Level Page 3

It is pretty easy to get the child pages for every page, but getting only the child pages for that specific tree seems to be pretty tough with wp_list_pages.

Any suggestions? Please let me know if you need me to clarify anything. Thanks a ton.