Kind of a brute force hack, but why not? A Kinesis Freestyle2 with Bluetooth and a 20" cable might work, except that you'd have to fiddle with the cable across

Kind of a brute force hack, but why not? A Kinesis Freestyle2 with Bluetooth and a 20" cable might work, except that you'd have to fiddle with the cable across your lap every time you got out of the chair.