PDAs for a Disabled Man?

Ed-Wars asks: "I work for a man who suffers from ALS (Lou Gehrig's Disease) and is mostly paralyzed, including a very limited ability to speak. He is looking for a portable device with a keyboard which will allow him to communicate with others while he is away from home. Wish-list: cheap, good sized screen with highly visible lettering, large and widely spaced buttons, ability to store/retrieve commonly used statements. It doesn't need to be high-powered or have any fancy graphics, again cheap is important. Text-to-speech could be useful, but is not necessary. Any suggestions you could give would be very helpful. Thanks!"