First things first, English is not my native language so I apologize if I'm not very clear.
When using a notebook, I usually don't hide the taskbar for three main reasons: quick launch, clock, and battery notification. I like my app launcher (in this case Quick Launch) to be always visible, so that to launch a program I only need two actions: locate the program's icon and click the icon. Setting to auto hide means more actions: show the launcher, locate the icon, and then click the icon. I also need the clock to be always visible as a quick reminder for lunch break or other small things that just don't worth having a dedicated reminder program for them. The battery notification is to remind me when I need to plug/unplug the adaptor.
But I also have a netbook, and with netbooks, screen estate is very limited, so I choose to auto hide the taskbar. I'm OK with trading quick launch for screen height, but I still need the clock and battery notification to be always visible. So, what I'd like to have is a small bar that stays on top of the screen, about 12 pixels or so in height, just to show the current date, time, and battery status. The bar should also resize the screen work area so that it doesn't cover the titlebar of a maximized window. I attached a simple mock up to show what I mean.
Additionally, it is also nice if the battery status info changes color, let's say red when in critical battery level and green when the battery is fully charged. I also prefer 24-hour format.
Similar programs are StatBar and Rainlendar I believe, but they are too complex for what I need.