We have had small cheap laptops with 7" screens, like the Asus Eee, for a while now (
Ultra-cheap ultra-mobile laptop comparison matrix). The recent trend is to 8.9" screens in a similar form factor, available this summer. For example, the
Asus Eee 900 has a 1024x600 8.9" screen, and the
HP UMPC 2133 has a 8.9" 1366 x 766 (WXGA) display. These are both conventional clamshell laptops, except for their size, but perhaps other vendors will introduce similar tablets or convertibles.