The Gemini is based on a G3 Clamshell iBook (300/366/466MHZ) - it has a integrated touchscreen and was built to support disabled people. The Gemini iBook was the second Mac modded by Assistive Technology Inc., the first one was called Freestyle and featured a PowerPC 603e Processor. I bought my 366Mhz Indigo Gemini in 2009 and carefully upgraded it with a DVD Drive and 120GB HD.
The Gemini has no internal keyboard, there are a couple a new internal wires, so the upgrade process was very delicate.