To quickly jump in here again and point out a few issues ... mainly legal in nature.
Local, informal confederations of schools informally sharing services and hosting between them raise a number of issue.
1 - If data from school A is hosted at school B have you told the parents? Does your Data Protection Policies reflect this? When something goes wrong who is legally liable?
2 - Access to resources shared between schools is a problem. Without a central decision-making person it creates tension between the schools. Who will pay for this person and who will set their targets? A committee? They work so well ... Would it be a single school? How do you stop staff in that school putting pressure on that individual for preferential treatment for them or their school?
3 - Who takes control over the safeguarding aspect of things? What happens if techie from school A changes a setting which, indadvertedly, allows a child at school B to see something seriously disturbing?
There are a lot more things I could put but I don't want to be seen as being a blocker on the idea. It all boils down to this would need to have to be on a commercially contracted solution, either as a separate business or sold from a lead school. It becomes a managed service in all but name.
There is a lot of mileage on this ... a lot of mileage on sharing expertise, resources and time ... EG shows that ... it is just hard to get the ball rolling, is fraught with some legal issues and is subject to politics between schools.
I don't have a huge amount to say on the subject, other than I really hope people are not left with offsite support as their only port of call.
I also really do not want to see people reliant on VDI solutions either. It's a good system but not for entire schools as it writes off too much ability.
And the less said about "The Cloud" the better. It's a buzzword I'd like to see die off very soon because it's definitely misused and certainly not a be-all and end-all solution.
I would plan for each high school to host three primary schools close by with VDIs also you can licence Microsoft per groups of schools now but keep the high school as fat clients.
Large companies have large WANS which function just 'fine'.
Bringing schools together essentially creates the managed service. It makes sense to do this in many schools but as Dook says there would be lots of implications.
BSF being a prime example, we would have to pay per user which is an immense price, our budget was 170K last year and that still wouldnt of covered the cost of BSF for our school. You can also imagine how we would have struggled this year with the budget cuts. If the likes of cloud computing is the future then when the costs are down we will look at it but it is still relatively young.