I can run Skyrim in keyboard mode and use Xpadder to map the buttons to the controller. This seemed great at first as I can make left bumper a modifer (as well as Alt) so it works as Run but also shifts the mapping so that when I'm not holding it I use the D-pad mapped to Q, I, P and M for Favourites, Inventory, Magic and Map (I use the SkyUI and QD Inventory mods) and when held it changes to 0,1,2,3 allowing me to assign items in the Favourites screen (I use the Categorised Favourites mod) and quick select them in game. I can also use the Start button as Auto-Move and X as F5 (to Quick Save) when holding left bumper.
Unfortunately it gets a bit confusing as the onscreen prompts refer to keys instead of the controller buttons and various other problems crop up such as:
Navigating the Inventory in controller mode it uses the triggers to change tab but in keyboard mode I have to use WSAD, which is mapped to my left stick and it's always accidentally triggering left or right, changing tab when I'm trying to go up or down. I also can't assign the highlighted item with the left and right triggers without first moving the mouse cursor (mapped to my right stick) over the item, which I obviously don't have to do in controller mode and is a major pain.
In keyboard mode, I have to use the scroll wheel to zoom the map. I can map the scroll wheel to up/down on my right stick (when holding the left bumper) but it's not at all smooth. In controller mode zooming can be done smoothly (with the triggers I think, but I can't recall just now).
Picking locks with WSAD mapped to the left stick is too hard as it's overly sensitive (works fine in controller mode).
I can no longer change tabs easily in the Journal/System menu and have to move the mouse pointer (mapped to my right stick) and left-click (mapped to my right trigger) which is very fiddly.
I imagine the controller mapping is hard-coded into the game and can't be modded, so I hope Bethesda are reading and will consider changing it so that it incorporates using left bumper to shift (and Run) as I'm currently doing, which would enable access to extra commands and make Skyrim much nicer to play with the controller.
