RE: reducing font size

[Drew Adams]

> I'm developing/writing my own theme which will have everything in it
> that I want that other themes don't have in them! Sounds arrogant but
> its quite easy to do using "M-x customize-create-theme", and its fun!:)
> 
> Anyway, I use tabbar and want to have the font of that and the mode-line
> smaller, but I can't find out how. Can anyone give me some pointers as
> to where to look please?

This might be one place to start:
http://www.emacswiki.org/SetFonts#ChangingFontSize

Probably you just want to customize the relevant faces, setting their fonts to 
the sizes you want. E.g., use `M-x customize-face' and change the `Height' 
value.

For the mode line there are two faces: `mode-line' and `mode-line-inactive'.
For tabbar.el, it is probably face `tabbar-default' that you want.