My suggestion to you is to check out what other public institutions have selected as their public use PC and laptops. For example, the KCLS Library system was voted Library of the year for 2011 by that library journal (which is probably one of their field's major publications) and was also the #1 busiest library system for 2010. That library system has lots of internet terminals which are basically a basic PC in a small footprint and an LCD monitor with privacy screen. They have laptops for loan which you merely present your library card and you get the laptop for 2 hours after which you return it, wait out the 30 minute cooldown, and check it out again. The laptops they use are a mixture of Dell, Compaq, and HP because they don't want to put all their eggs in one basket and they are collecting data on which brands to use in the future, as well as have the brands compete for the next contract. The advantage of different models also is that library patrons aren't bored with just one laptop model.
I assume that part of the $1,000 budget per unit includes the following:
a. The laptop/PC itself and OEM operating system
b. The maintenance warranty plan as the laptops are only as good as the maintenance plan lets them exist
c. Additional software: MS Office, security software (lojack), antivirus, anti-malware
d. Additional hardware: PC locks for PC base units, new central printer, carrying cases for laptops, wireless nodes, ethernet or wireless for PC units.
e. Three PCs reserved for maintenance & testing, administration software, tools, SpinRite software. One of the reserved PCs can be considered as a spare replacement if any one regular PC goes out of service. Of the other two PC, one is for network management and the other is for general use at the IT staff/maintenance site.