I think you'd have to create page-templates in the /pages/ folder with a page-template in the parent folder that points to the actual page-template in the /pages folder as well (2 files so far, but only to maintain consistency with how Carrington organizes itself). Then, when you make the page in WP, you select the appropriate page template (which is a normal WP feature/function/ability).
To make it extra clear:
1. WP page is directed to use a specific page template that appears in the Carrington parent folder.
2. Parent folder includes a placeholder page-template that simply forwards into the /pages/ subfolder.
3. Inside the /pages/ subfolder is the actual page-template with all of the code you want to use to make that page unique.
And, of course, you'd probably create the above 3 in REVERSE order.
On the page-template IN the subfolder, you'd just hardcode everything that the framework doesn't handle. So, for example, if your header is common with other parts of the website, you could continue calling it (and it would use either the page.php or header-default.php etc. template in the /header/ subfolder). Likewise with the footer. But since you want different sidebars for each different page, you'd have to hardcode the differences either directly in the page-template inside the /pages/ subfolder
OR, if you want to stick with the Carrington idea of organization, maybe put the different sidebar code inside the /sidebar/ subfolder knowing that it won't automatically get called under any "contexts" without you adding something like:
<?php include (TEMPLATEPATH . "../sidebar/sidebar-for-services-page.php"); ?>
...IN the page-template IN the /pages/ subfolder to manually call it.
The more you atomize your code and set up linking like the above, the less duplicate code you have (allowing you to only make changes to one shared file instead of multiple files that include the same element). Only problem is, you kinda have to keep track of the web you've spun. There's probably also a bit of overhead involved in having your server access different templates to build each page but as Carrington says, it isn't too much and you should be using caching anyway.
Hope this helps you understand Carrington as I do! Cheers.