They say that Microsoft never intended for us to be able to create publishing sub site templates, not even in MOSS 2007. But by turning the publishing feature off, we were able to get around and save the sub site as a template, create a new one from said template, and then turn the publishing features back on for the newly created sub site.
(Another trick was to backup the sub site in SharePoint Designer and then restore it over a blank sub site. But that option is gone in SharePoint 2010, as well.)
So the only way I found to make my life a bit easier as as Designer and to reduce the amount of repetitive work is using the Manage Content and Structure tool.
2. Create all pages and components (lists, web parts, etc.)
3. Once you have completely created your publishing sub site, the one that is going to serve as template, go to the level right above it and select [Site Actions] > Manage Content and Structure
4. Click the row where the name of the sub site displays and select Copy from the pop-up menu
5. Select the destination where you would like to paste the sub site to
6. Access the newly created sub site via your browser (you will need to leave the Site Content and Structure page), rename the sub site, edit the home page, edit any content query web parts (if any) that you may have on the home page or any other pages to the case, and make them point to the sub site’s lists and libraries, instead
Important Note: When a sub site is created this way, web parts such as the Content Query Web Parts will still be pointing to the original sub site used as template for creating new sub site.
That’s it. The only thing to keep in mind is that when you modify the path to the appropriate list or library for a content query web parts by using the [Browse] button you will lose all the other settings for said Content Query Web Part (for example, filters, etc.). To prevent this from happening, edit the path manually (for example, if the path to is /SiteName/SubSiteTemplates/SubSiteTemplateName/Lists/ListName and it should read /SiteName/NewSubSiteName/SubSiteTemplateName/Lists/ListName, type in that one section of the path; this will prevent the filters from being cleared.)