This may be more simplistic than you were thinking, but what about using Wordpress authors for your Artists? Than, create a Custom Post Type for timeslots or stages and then a category for that post type and assign one to the other, i.e... assign 9pm (new post in "timeslot" custom post type) to the Side Stage (custom post type category) with the author (artist) We Were Promised Jetpacks. Anyway, not sure if that helps at all, just a thought. You can do a lot with author.php and $curauth, adding fields for the author profile, etc...