Single channel systems like extricom and meru were developed to solve a roaming issue that doesn't actually exisit on any properly designed wifi network. 98% of WLANs out there are standard multichannel architectures, roaming works in MCAs - it's what wifi is built for afterall. Also consider what happens if you have a complicated problem with a SCA the only people that can help are generally the vendors themselves. I'd recommend you compare the likely school candidates, Ruckus, Aerohive, Xirrus (Cisco and Aruba are very expensive). Give them all a call they should be more than happy to setup a demo.