Bars for displaying health/tiredness/happiness/whatever are certainly possible. Yeah, I like the idea. At some point (after a lot more bugfixing) I'll probably make a new control, PercentageBar. It will be fully graphical, settable to percentage 0-100, with two background colors (gray/black and dark red) and a few bar colors (black, green, blue, yellow, orange, red, off the top of my head). That way the bar color can be chosen based on what range the value is in, so for instance as a value dropped you could see the color go green->blue->yellow->orange->red.
What about the inventory panel (Item Management screen?) would you spruce up?