Hotbar highlighting / switching with modifier keys?

[SamSmoot]

1. I need to have my keyboard layout duplicated by the hotbar button positions, so I can remember which key to press by it's matching screen position. Because if this, I can't have three different hotbar buttons representing one keyboard key.

First idea: 3-4 separate hotbar blocks, one for normal, shift, ctrl, alt spread across the bottom of the screen.
One problem with this is that it would mean taking my eyes off the action for the button blocks to either side, and I still don't know which one is active.
Question: Is there a way to have each block highlight when the corresponding modifier key is down, so I know when I have the right key pressed? (Sort of like groups are highlighted in controller setups.)

Second idea: One set of keyboard-matched buttons in the center of the screen, and have it switch abilities depending on the modifier key that's down.
Is this possible? Example: Shift buttons appear only when Shift is down, etc.