I recently began taking part in an rl group of historical fencers, and we are all pretty much medieval era geeks. But one thing i noticed that was different from the historically accurate fencing, and the PrC in Layonara, is that historically, a fencer would have used a dagger, his weapon's scabbard, a cloak, a buckler, or any other object that was handy and would give him an upper hand. Now I know that letting someone run around with all the duelist bonuses and a tower shield would be a very powerful class compared to a normal fighter, but maybe there could be a weapon sheath or cloak item that would give a defense bonus for the weapon sheath, or for a cloak, a smaller attack and defense bonus.
Just a thought,
Teo