i myself have only used Microsoft security essentials, i have never gotten any type of virus of attack from hackers, but i also browse the internet carefully...common sense is the best anti-virus
it wont harm the hard drives unless its a very powerful magnet. "The same goes for hard drives. The only magnets powerful enough to scrub data from a drive platter are laboratory degaussers or those used by government agencies to wipe bits off media" source for quote...
the only thing that i could find is a case called gripster and lapworks, and from what i know, they only make cases with handles for ipads :( but maybe you can rig one of those or something, or just attach a handle to your tablet?