|They 'fixed' the old method of keeping quest items, mostly.
To keep quest items now, go through the same process of filling up with 125 items, and having it drop to the ground. Now, it'll pop back into your pack after a second on the ground. Get it on last target, have "i wish to lock this down" spoken with the targetting cursor up, have it drop to the ground again, and tap your last target key while it's on the ground in a house you own. It'll pop back into your pack, this time while locked down (which may have interesting applications of its own.). Then, use an interior decorator on the item in your pack to raise it, and it'll appear on the ground at your feet.