TinyMainbarInfo will put the mainmenu bar to use by overlaying interesting info when it is not in use. As soon as the mouse moves over it the default micro-buttons re-appear.

Cataclysm, and WotLK compatible.

TinyMainbarInfo

Shows:

Session Playtime with player status indicator (away, busy, available)
Player Coordinates
Latency
Money
Lowest Durability
Blizzard Average Item Level / (equipped only itemlevel color coded by quality)
Frames per Second
Memory used by the Lua environment (addons)
Total Bandwidth used by the client (up+down)

F.A.Q

Q: Why are there 2 different average item level numbers? What do they mean?
A:

Blizzard calculates average itemlevel considering the highest level soulbound item owned by the player
(uncommon quality and above) for a specific slot regardless of location (can be in bags or bank).
This is the average itemlevel shown on the character screen and used for LFD.
TinyMainbarInfo will show this number in white font for convenience so you can see at a glance how far you are from that LFD unlock.
In addition TinyMainbarInfo will show a second number in parenthesis
that takes in account only the equipped gear, color coded by quality.

TLDR version
First number corresponds to the highest average level of gear the player "owns".
Second number corresponds to the average level of gear the player has actually "equipped at this moment".