Been there, doing that (Score 1)

I feel your pain, really. Before anything else, you need to document. Document everything. Any conversation, email, phone call that you have. You need a good IT system that links inventory to tickets. You need DATA. Schools are highly data-driven. Look at Spiceworks, it's free.

Ask for a copy of the IT budget for planning purposes. Make a beautiful plan of systems replacment cycles, infrastructure needs, projected costs, etc. Make a 5-year plan for your technology. Show it to *everyone*.

Make policies & procedures. Don't add a lot of crazy ramblings or jargon, keep it plain and simple. Show that to everyone too, and hopefully someone at the top will help make it official board-approved policy. Make a nice presentation about how your policies will reduce labor costs and increase hardware life. In education, the squeaky wheel gets the grease. You also need to talk about how these changes will make things simpler for the teachers. Find model schools out there that have done great things with technology, and get copies of their policies, their student:device ratios, and their device:IT ratios. Talk with your state DOE, get on any mailing lists or Google Groups for school IT staff in your state/region. Isn't one? Start it! Just cold-call other schools and talk to their IT departments. Yes, I'm serious; most good school techs are highly collaborative.

And if you can't change policy, then you need to find a way to make this mish-mash work. Consider desktop virtualization -- whatever junk they buy becomes a terminal. And how about using the health insurance policy model? You get the terminal we buy for you, or you get a $500 bonus check every 5 years to buy your own non-supported personal device to run the virtual desktop.