I'm developing a site that requires some menu items to occur in two different places within the primary links:
Section A
-- Introduction
-- Testimonials
Section B
-- Introduction
-- Testimonials
Testimonials
-- Section A
-- Section B
So 'Section A > Testimonials' and 'Testimonials > Section A' are the same node. In fact, I've tried it as a node, a Taxonomy term, and a views-based page. Same result. D6 assigns just one active-trail, and it's often not the one I want to show as active. I understand a little of what's going on in the background. D6 is using only the URL as a key to determine the current active trail. In my testing, the active-trail isn't always determined by which comes first in the menus... but regardless, it's not something I want to rely on.
To date, I haven't found a drupal-based solution. Menu Trails is a nice module, but it only helps when your node isn't in your menu somewhere.
So here's my non-drupal solution. Tell me if it's a bad idea. I'm going to create a placeholder node for each item in the Testimonials menu, set the path to something like "testimonials/redirect/section-a", and the use mod_rewrite to redirect over to "section-a/testimonials".
With this solution, I will have no duplicate paths in the menu. I'm just hoping this doesn't somehow hurt my SEO.