Expanding on pile0nades' idea (http://userstyles.org/style/show/369); this should remove virtually all the jerkiness of the greasemonkey gui and makes it a little bigger.
Fenster in Schwarz mit weißer Schrift, Boxen in Blau mit weißer Schrift Highlightbalken in Schwarz bei Hover und Gold bei aktuell Window in black with white letters, Boxes in blue with white letters Highlight bar in black and gold to hover at current
For a long time, I found the default Greasemonkey icons to be hideously ugly, so I made my own in the style of 15x15 emoticons that we all know well. You can also modify this style to change the toolbar button with your own custom icons!
A matching textual icon for Greasemonkey, to match Stylish statusbar icon (normal text) by dougeeebear.
Modification for Greasemonkey (https://addons.mozilla.org/firefox/addon/748) status bar icon. Icons are grayscaled and tightened to best suit the GrApple (http://www.takebacktheweb.org/) themes. 2009.06.12: FIXED disabled icon is now actually grayscaled.  2009.03.15: Initial release.
Removes the extra space on the Greasemonkey status bar icon.
Mainly copy & paste job, original code taken from here: http://userstyles.org/styles/5704 Original GM icon taken from GM version prior to 0.8
- Removed the large margins on the sides of the Greasemonkey icon Let me now what you think! NOTE: since version 0.8.20090920.2 the extra spacing is removed.
Allows you to Customize the text and background image of the GreaseMonkey UserScripts list. Features: + Background image will be a faded Firefox logo with shadowing + Supports a huge list of Fonts (discussed below) + Image supplied in default code is hard-coded - allowing you to view the background, even when offline! + Background image is static and is centered on the window. = Optional - Text size of the popup will be larger (must uncomment) = Optional - Bold text for easier readability (must un-comment) Fonts Supplied (Supported): - Currently, I supplied the following Fonts in the Code: 1. Segoe UI (User Interface of Vista) 2. Calibri (Text of Vista) 3. Verdana (XP Font) 4. Helvetica (XP) 5. Tahoma (XP User Interface Default Font) 6. Arial Global Font Applies to: + Scripts Listing + Grease Monkey User Scripts Manager Left Window Pane + Included + Excluded Browser Versions: - Works on Firefox 3 - Works on Firefox 2 Get scripts from userscripts.org
Just an icon adaptation of; http://userstyles.org/styles/5704 , credits goes there... Although it's named Grease-Monkey, I don't like to see a monkey lol'ing me all the time. Since UserScripts.Org FavIcon represents scripting "more accurate" than the monkey IMHO, I simply adapted above userstyle with UserScripts FavIcon... If you don't like the colors of the icons, simply download http://userscripts.org/images/script_icon.png, open it with a decent image editor with png transparency support plus hue/saturation controls. Play it as you like and re-encode it with http://www.motobit.com/util/base64-decoder-encoder.asp. Then replace the desired icon with your version and remember to share it here ;-) ...