In the PlutoHome distribution there is built in checks in some of the scripts that enforce the same Kernel version on the Core and the MDs. I am not sure if this has been removed for linuxMCE or not, but it is something to look out for.
Well I'm not sure if that is the case. I know the kernel on the core machine has the module I need for the media director (forcedeth). If the Core must have the same kernel as the MD, then my media director should boot up and load the forcedeth module unless the module is there but it is just not loading for some reason.