Well, at some point (if we believe DC ONE MILLION) Kal-El will leave Earth to journey among the stars when he loses all those who are closest to him to the ravages of time (Kal will live to see the 853rd century. Wowzers. :shock: ), but in his place will rise his heir and founder of the Superman Dynasty, Superman Secundus. Now, whether or not this is Kon is still kind of up in the air, but I have a sneaking suspicion it's him.
Your idea of Kon going off and forging his own superheroic identity does sound interesting though. Maybe you could put it together as a fanfic for a site that focuses more on the post-Crisis Superman Family.
-Def.