I can certainly see the value in a tablet that runs Android and Windows 7. You can use Android when you want to mess about on the Android Market or play some cool mobile games. When you need to use your productivity software, you can boot over to Windows 7 and get access to all the software you normally use in the office.
A cool new tablet called the Evolve III Maestro has surfaced that will boot both Windows and Android, and it adds in a third OS. The tablet will also boot MeeGo, which will make the Linux faithful really happy. More is often better in the eyes of the consumer so having three OS' to choose from will appeal to many shoppers.
The tablet runs an Intel Atom N475 CPU, 2GB of RAM, and has a 32GB SSD for storage. The screen is 10-inches wide and the rig has WiFi and a 3G modem inside. The tablet is expected to ship in Q2 2011. Exactly what the thing will cost is unknown; it sounds more like a netbook than a pure tablet to me.