Shrinks the Gmail sidebar text and trims some distance off the bar, increasing the main panel area. Hovering over a pane (i.e. the Chat pane) causes it to expand to a larger size so that you can interact with it more easily. Once your cursor leaves the pane it will shrink again. These styles obviously don't play nice with every browser, but should be fine in Mozilla based browsers. Stylish CSS attached.

Notes:
1. I only tested this at the few resolutions I had available, which did not include any widescreen aspects (though I did stretch across dual monitors) or resolutions over 1280x1024. I think it should work on hi-res widescreens, but I haven't been able to see it yet.

2. It's a little rough still, but the ground work is in place. I wanted to make it available for anyone who wants to play with / improve it.