I've got this to an actual prototype now, in terms of components at least, shown in the image below.
I'm interested in any feedback or advice anyone has.
At the moment I'm using cheap in-car LCD screens, and they're very easy to hook up to the RCA video output. This means the quality isn't great, but I'm happy to accept that for a low cost tablet with easy to replace parts.
I've added a touchscreen in front of the LCD, but haven't got the driver installed yet as I need to modify the kernel to do so, which is a a bit beyond my skills at the moment. (But it's a compelling reason to find out how, and not just put it off for another 7 years)
Once that's up and running I'll focus on making a tablet-friendly interface, e.g. I have some mildly interesting ideas on how to improve the keyboard used on the ipad.
As I mentioned, all feedback, knowledge, suggestions and whatever are greatly appreciated. I'm something of a noob at electronics, and reasonably experienced with coding, if that helps focus your responses.
http://img856.imageshack.us/img856/4559/elmprototype.jpg
