Filmstrip to replace navigator - how?

I have tried to understand navigator.tpl and it appears that it is limited to showing the next, previous, first and last thumbs only. It cannot show the current picture, and it cannot show pictures that are ahead of 'next' or 'previous'.

What I want to do is a filmstrip (like the one in Picasa or iPhoto) that shows the current picture and several pictures ahead or behind. It would also be useful to have a picture number behind the thumb so users know where they are in the album.

I managed to get the current picture into the navigator by some rough hacking:
{g->image item=$theme.item image=$image maxSize=40 class="current"}
however, I cannot get the other thumbs to show.

Can anyone help?

Using Matrix theme, gallery2

This is the link of the user contributins themes page:

http://codex.gallery2.org/Gallery2:User_Contributions