First, the Al's Tools demo store is not using pre-defined searches, it is using JavaScript pull-downs that link directly to static .html pages created in ShopSite to contain that particular kind or brand of product. You can see how these pull-downs were created by looking at the source of the frame that contains the pull-downs (
http://eval.shopsite.com/shopper/als/topnav.html), it's pretty simple JavaScript actually.
As far as misspellings causing shoppers not to find items, this is a good reason to add common misspellings for words your shoppers may try to use to find a specific product in that product's Search Keywords field (ShopSite Pro).
You can also keep track of your search performance via the Search Logging feature (Pro, v9 and newer, configured/enabled in Preferences -> Search Settings -> Search Logging) to see what search terms are most common and to see what search terms may not produce any results, then you will know what terms your shoppers are using and you can add those terms and misspellings for those products to the Search Keywords field for the products that you want to lead the shoppers to.
-Loren