I just graduated from the Illinois Mathematics and Science Academy (IMSA).
IMSA has implemented a 1-to-1 program over the past few years, and has been attempting to make use of convertible tablets by requiring every student in the class of 2010, 2011, 2012, and 2013 to have the convertible functionality. This experiment has shown that the tablet functionality was not being used in the classrooms enough to make it a worthwhile investment. Starting with the class of 2014, IMSA will be moving to standard laptop configuration.
Personally, the extra cost that the convertible functionality adds is not worth it. It provides some WOW factor, but then it gets boring after a while and doesn't get used much.
https://www3.imsa.edu/helpdesk/1to1
As for basic spec, I would say, 12-14" screen, full size keyboard, good battery.
Feel free to PM me, and then I could put you in contact with some members of the administration who would be more than willing to answer questions, or answer questions from a student prospective.