I haven´t seen a lot of these pieces online, on Ebay or elsewhere, yet at the same time, as the label was wider distributed, more and more pieces from recent collections could be found online. the pieces that you usually find online are those that are neither highlights, nor staples/basics - that is, t-shirts with printworks, dress shirts, ocassionally a sports jacket and classic suits. It is usually the case that particular stuff always sells, such as the infamous "Napoleon" jacket, the tuxedo with wolves-embroidery in the back, the pink leather blazer or the black Hussar jacket from this season.
I think Dior is still somehat in the transition phase - they are slowly building up their "commercial" vocabulary (that is, anything grunge-y in between A/W 2004 - S/S 2006 - jeans, jersey, easy leather jackets in terms of RTW, as well as sneakers, leather goods and accessories), whereas the show collection is going to be more experimental, as seen with F/W 2006. Of course they could never afford producing a collection that is solely build around catwalk imaging, who cares though, as long as there are commercial pieces to be found in the showroom?