Instructables is a great diy website with tons of downloadable howto’s including everything from craft to tech. Love this site so much I bought a cheapo membership.
Great tutorial with pics!
Custom Android tablets – sweet!
Using Beaglebone/Beagleboards to create custom tablets running either Android or Linux. Definitely a possibility to use a Raspberry Pi as a base as well. Attaching Arduino boards to the tablet with sensors and or shields.