"Castle have stockpiled enough motherboards to last for at least a couple of years, since you're allowed to sell things that you already had in stock...."
Unfortunately, it's not that clear-cut. The ruling states that a non-compliant product may not be "placed on the market" after 1/7/06. The general interpretation of this is that a product is placed on the market when it is in its final form and ready for sell. Therefore, an assembled Iyonix in stock can still be sold, but it would now be illegal to use an existing non-compliant motherboard to build a computer and then sell it. Of course, a creative work-around could be to sell the system components separately and then charge an integration fee to assemble it. This may even be why Castle started selling the motherboards separately.