A lot of this is a matter of taste Sony Vivo are good machines but costly, Toshiba and Compaq both make good machines as do Acer, havent used any others.
Watch out for battery life, but most are at least 1.5hrs when off the mains
If your going for 100 machines I think you would get a reasonable discount maybe 20 - 30% maybe more.
Try the manufacturers direct sales that way your cutting out the middle man.