Creating a View All Products Link

One way would be to create a "All" category and assign all of your products to that category. The easy way to assign all the products to the "All" category would be to use the global product changes, clicking the top all products and go to the bottom and assign the selected products to the "All" drop down category.

I went the route of creating an "all products" subcategory in each parent category and then copied all appropriate products into them.  I'm still convinced there's a way to do it without creating categories, for instance by constructing the "ideal" search results URL.  As an example, I tried building the following search result URL that would produce the products from four different categories, but the resulting product set was a different number of products that the total of those four categories.

http://stuffington.com.mytempweb.com/shop/pc/showsearchresults.asp?idcategory=38&idcategory=39&idcategory=40&idcategory=60&priceFrom=0&priceUntil=999999999&resultCnt=12&order=4&Submit.x=32&Submit.y=9