In Daggerfall, a factional NPC exists known as http://uesp.net/wiki/Daggerfall:The_Great_Knight who is the leader of the Blades and brother of Lady Brisienna. I don't think he actually manifests himself in the game, and I highly doubt Bethesda remembered this guy when writing Oblivion's quest line, but do you think by any chance he could be a younger version of Jauffre? Assuming Martin is in his late 20s/early to mid 30s by the time of Oblivion, the time during which Jauffre was grandmaster of the Blades definitely could overlap with the years the events of Daggerfall are set.
Of course, I just like to pretend and love it when TES games reference one another. There's presumably no other information to follow off of, but I was wondering if anybody else had any thoughts about this.