While I agree for the most part, have personal experience (more than once) with the following proving to be roadblocked:
'The VM solution would allow such teachers to get up and running on a personal computer and also allow access from other networked PCs'
Even if a laptop was appropriatley configured with a VM (pick your Linux distro) with Moodle + other, there was only one internal switch and 3 ports on that switch would allow port 80 hosting on the entire network. When one runs into the 'uber-paranoid network administrator', no such thing possible without their direct involvement. In two instances, the entity had 'suffered' from Code Red and Nimda - network worms that brought their entire WAN down and very painful from which to recover - and there was NO WAY that network admin was going to allow it.
So ... this to say ... one size doesn't fit all! :|
'spirit of sharing', Ken