(Under construction - just musings at this point)
How much for a centralised Mac server?
Less than $10K. Probably around $6-7K for the hardware plus some setup time.
Is it worthwhile?
Most Mac based loop schools already have local Mac servers. For those that don't (i.e. using Smartnet or Windows based servers) then it's a question of how much would they be willing to pay for access?
A hard one to judge as they're also probably not aware of how much benefit there is to having a standardised deployable image (but once they do it, they never go back!).