Does the school you wanted to help out have a wired network? In that case how about still sending the five laptops to them, but add a usb to ethernet adapter into the bundle so one of the XOs can get network access, which should hopefully allow the rest to connect via that wired-in one. (or buy five adapters and have them wired in individually if that works better)
Adapters are not that expensive, $25 for one type:http://studiofibonacci.com/index.php?ma ... 8f34c180a2
(I'm not affiliated with the place, but the owner is an XO owner and forum member at XO News)
Of course the biggest thing about the XO is the collaborative features from the mesh networking, so even if they are in their own mesh network with no outside access they'd still be usefull to the school, I would think.