I like the game with both grass and shadows turned off, but notice in both the "Ragged Flagon Cistern" as well as some Dwemer interiors there are still shadows cast by overhead lighting. Is there any way to remove these last remaining shadows? I already have all of the shadow settings disabled in the Skyrim.ini file (read only) but still see them here and there.

There are two kinds of shadows, those the are caused by the object casting the shadow, then the shadows that come from the light sources not lighting up an area completely. So, in other words, these are not shadows per say, but more an absence of light. It is something that you see better if you ever make an interior cell and add light sources to it. Note, these light sources are not always lights, but just points that emit light. Anyway, since this is an absence of light, the processing power to resolve those shadows are not the same as object related. shadows

You could eliminate the shadows by cranking up the ambient light for each cell, but that would just be overly bright and washed out.

However, if you are trying to get more performance, you might look to a mod that removes the excess light sources from a cell. These mods have been made for Oblivion, Morrowind, I think one of the Fallouts had one. Anyway, the light sources can be a drain on your machines resources and can affect game performance if your rig is not up to the task. Note, if you remove the excess light sources, you may, or may not, see more shadowed areas.

A "point that emits light" is the perfect description. It's not a problem nor really noticeable when shadows are on, it just stands out more with my current settings. It's just more of a preference of mine (no grass/shadows) rather than a performance issue. (I purpose-built this rig strictly with gaming in mind)

"You could eliminate the shadows by cranking up the ambient light for each cell, but that would just be overly bright and washed out."

I tried that, but it ruined the overall "feel" of the area that I tested it on. Can the light source like , say, in the "Ragged Flagon Cistern" possibly be changed or swapped out with anotherlight source through the CS?

I've just released this: http://skyrim.nexusmods.com/downloads/file.php?id=16464

Downloaded and installed the mod. Went to the Ragged Flagon Cistern and no more ugly shadows! Many thanks to you Mr Reiper!

(Skyrim Nexus vote and endorse soon to follow..)