There will be a successor. It's going to take at least 1-3 months to phase out the older tablets but that will only occur after introduction/mass production of the new one. The transition will probably be similar from the TC1000 to the TC1100.
The 915 chipset supports PC2700 and PC3200 DDR memory but capacity is capped at 2GB. The Centrino package may include either the Intel PRO/Wireless 2200BG or 2915ABG cards. PCI Express, Gbit LAN, x16 Graphics, and TV Out.