I am not a theme designer but was recently looking at a site discussing scalable HTML:
http://www.mutinydesign.co.uk/scripts/scaleable-html-and-css-guide-part-1--introduction---4/
If you use the pull me tab on that site you will see what it does.
You will see that this technique scales the layout and performs much better than increasing the font size within a fixed layout.
I am only posting this as I have not seen this technique used before and thought it may be provide ideas for some of the theme developers.
Jeremy
Thanks for the link, Jeremy!
I have used step by step font size increasing/decreasing/reset with three buttons but this looks much more flexible. All this kind of new ideas are welcome.
You could still use "three size buttons" but you could scale the layout as well as the font... I thought it was an interesting technique, though the author still has to post his tutorials on the subject....
Jeremy
What do you think of the case against Text resize buttons?
Don’t Provide Text Resize Widgets — Educate
Joseph

What do you mean? Can you explain or maybe attach a screen shot?
Joseph
PS.- What I agree most with in the link I posted is the stress on Educate users.
I mean setting options from toolbar as explained in that document and in ie right bottom corner...I had not read that article before and it was excellent.
BUT: Jakob Nielsen is the Usability Guru for websites and the buttons are not so important as the ability to change font size if it is too small or big. These are his “Readability Guidelines” for Website Font Size:
Do not use absolute font sizes in your style sheets. Code font sizes in relative terms, typically using percentages such as 120% for big text and 90% for small text.
Make your default font size reasonably big (at least 10 point) so that very few users have to resort to manual overrides.
If your site targets senior citizens, use bigger default font sizes (at least 12 point).
If possible, avoid text that is embedded within a graphic, since style sheets and font size buttons do not have any effect on graphics. If you must use pictures of text, make sure the font size is especially large (at least 12 point) and that you use high-contrast colors.
Consider adding a button that loads an alternate style sheet with really big font sizes if most of your site's visitors are senior citizens or low-vision users. Few users know how to find or use the built-in font size feature in current browsers, and adding such a button within your pages will help users easily increase text size. However, because every extra feature takes away from the rest of the page, I don't recommend such a button for mainstream websites.
Maximize the color contrast between the text and the background (and do not use busy or watermarked background patterns). Despite the fact that low-contrast text further reduces readability, the web is plagued by gray text these days.
For more comprehensive information on website usability, visit Jakob Nielsen’s website at www.useit.com
