It seems like many (or at least some) manufacturers of PC casings are not that happy if they hear the three letters BTX in a row. Their distrust and resentment is quite understandable. Low sales not only at the beginning and expensive development of both design lines ATX and BTX at the time don't let these people be any happier. The purpose of introducing BTX headed by Intel, enhancing the airflow in order to use hotter processors, wouldn't make sense especially after Intel cancelled their NetBurst-based CPU's in the near future. Instead a very efficient and hence low power dissipating processor design (based on the mobile Pentium M) is favoured. Even in a faster dual-configuration ATX would be able to handle the amount of heat dissipation generated. Furthermore the case is that AMD 64 mainboards are not compatible to BTX because of their direct connection traces between RAM and CPU. If you want to know more about the whole situation go and hop over to the articles at Anandtech, Overclockers and TheInquirer.