Search inside a category

Theme: Business Directory, may apply to other themes too.

Request: Filter by additional criteria after selecting a category, and remaining inside the category. This is partially attainable today, but not completely, see below.

Details: In the BD template, you can click on a category (like Automotive in the demo), and get to a page with the category name, description and listings. I want to filter these listings by some additional criteria that doesn’t fit into sub-categories. I tried to do that with an Advanced Search widget, and it does filter, but the search takes the user out of the category in multiple ways:

• The search finds listings in all categories. To avoid, user must re-select the category he clicked on inside the widget.
• Once user clicks search, he’s no longer in the category page, and doesn’t see the category name or description.

I’ve tried to improve the situation by making the widget keep the current category (see
my question for implementation details). It does work, but introduces a few minor issues:

• This is done via a client-side script, which is sub-optimal.
• Subcategories no longer appear on the page.
• The BreadCrumbs bar loses the categories.