Often we hear feedback that the themes on WordPress.com are not wide enough.
For those asking for wider themes, we're curious: what motivates you to wish for a wider theme?
Is your site only showing photography? If so, what would you think about a photoblog theme like Duotone being wider to show a much larger image? Or would a normal theme that has image-only layouts be a better fix? For example, Twenty Ten has normal layout (two column with sidebar on the right) but when you view a single attached image you get a full-width, one-column layout with no sidebar. Would that type of layout choice work for you, or do you want the entire theme to be full-width where the front page, archives, single post all have the same width?
If you don't show photos, why does your site layout need to be wider? A text-only layout is actually proven to be more readable, usable, and accessible when it's constrained to a certain number of words per line. So in that sense, a wider layout would be a poor choice for your site visitors.
There is also the idea of a theme that can have a layout "type" per post or page. So in that case you get a default layout choice plus optional per-post/page layout choices in a module on the Edit Post/Page screen. What do you think of that for your favorite theme?
Your feedback is awesome—it makes us better. But in order to really meet your needs, we want to know more about what you're asking for.