So, you basicly want to create an autorig or some tools for enhancing rigging experience. May I sugest looking at already existing autorig, define what functions you want to start with and then explore what are the related operations needed to be amtomatic.
I mean, you may want to make the bone creation easier, so look in the MEL help about bones, bone creating, different flags associated with those functions. You may also want to make the naming of the bones easy, search for renaming functions.
Really, take it part by part. You might start with one precedure to execute by a shelf button and finish with a fully developped UI. But you have to start somewhere, no matter how small that step is. Break everything in small milestones instead of a big "let's make an autorig".