I should say that another option I'd like to have for searches is the ability to include/exclude whatever subcategory I'd like, instead of only searching in the single categories provided.

For example, searching for solar power supplies, I'd like to include General, Household, Farm & Garden, electronics, etc, and exclude Cars & Trucks (which for some reason respond readily to the term 'solar').

In other words, cut out the category drop-down menu and replace it with an array of tick-boxes.
Such an array would be handy for location search management, as well.