Clark County School District (Las Vegas area) with 1,859 iPads: http://www.ktnv.com/story/14709412/you-paid-for-it-ccsd-ipads
Shorewood High School (Seattle) to deploy about 1,600 iPads in 1:1 student program: http://www.shorelineareanews.com/2011/06/ipads-for-shorewood-students.html
Honywood School in UK with 1,200 iPads: http://www.t3.com/news/ipad-2s-to-be-given-out-free-to-pupils-of-uk-school?=56805
Hillsborough County of Florida with 900 iPads: http://www.tampabay.com/blogs/gradebook/content/hillsborough-details-ipad-costs
Foxcroft Academy of Maine with 530 iPads: http://bangordailynews.com/2011/06/02/education/foxcroft-academy-to-furnish-ipads-to-students-teachers/
San Domenico School (Bay Area, CA) doing 350 iPad 2s for grades 6-12, with pilots for K, 1 and 5th grade (thanks Chris Sokolov, director of technology, for email)