Found a tutorial. Yay! If anyone is interested the blog is called BluDor blog (just search the blog for magnets or look in the Baby/Toy section, or pm me for the link, not sure if I'm allowed to post it here). The spelling/grammar is very shudder-worthy but it's the closest thing i could find to what I've got pictured in my head!
Just bought some magnets online so will wait for them to arrive then get started..not that I need to add anything more to my sewing 'to do' list..it's already about a mile long