I'll be trying Dual Wield first just to see how well it works. If it turns out I prefer sword/shield better as I did in Oblivion and Morrowind, I may switch back to that. As for sheathing, whether the weapons go on your back or side depends on the design of the weapon. Smaller, lighter weapons like Katanas should go on your hip (fun fact: IRL, Katanas were designed to be sheathed at the hip so that the wielder could draw and slash in one fluid motion). Larger, heavier one-handed weapons such as War Axes should be sheathed on the back because let's face it, having a gigantic Daedric War Axe dangling from your belt just looked awkward.
Yup, and along with them being worn on the hip, they also had the curve of the katana(the blade) facing upwards, to make attacking in one motion easier, and in some cases, avoid a sword fight all to gather, and just kill the enemy by taking the katana out and slitting their throat. On that note, do you think katanas will be sheathed right if their on the hip, with the blade up? Be cool if they had a move where you just take it out and you could kill some one.