So, as I mentioned previously, I upgraded my phpBay Pro license to also give me access to phpZon Pro. So far, I'm really digging phpZon Pro. It basically enables me to both feature a single Amazon item in a blog post (by just knowing the ASIN) or I can create Niche Stores of multiple items using keyword searches.
There is, apparently, a new version of phpZon Pro coming very soon, but the version that I currently have supports both SearchIndex and BrowseNode searches, which is pretty helpful.
But, I was having a problem with search on a particular Niche Store site of mine. Basically, the site is a Jewelry Niche Store and I notice that when I did a phpzon tag and included a SearchIndex and BrowseNode that I was only getting a single item returned. It didn't really make sense to me. So, I posted on the PhpBay Pro Forums and got my answer in a jiffy. (The phpBay Forum community is fantastic!)
Long story short, it was because the items that Amazon was returning have a choice of size. What I found out is that if you are going to be using phpZon to search items that have a choice of size or color, you need to un-check the global option 'Filter Items that are Currently Unavailable' because Amazon can't check to see if the item is available until the selection has been made. I unchecked that and we were off and running!