Like I said, it's pretty simple right now, and may stay that way while I go back to tidy up and improve on InstapaperBeyond. I do plan to add a checkbox to the settings that lets you decide whether clicking the toolbar button copies just the current window's tabs, or all tabs as it does now. I would have liked to add a "copy to clipboard" button, but (as far as I know), Safari doesn't allow access to the clipboard in any fashion, even with something like ZeroClipboard.
The popup window could use some classing up, too… a little CSS3 animation/transition and some more consistent styling that isn't constantly being overridden by site styles. However, it's quite useful to me as is, so I'm sharing it in the hopes that others will find it as helpful as I do. Personally, I use it when I write posts, especially on TUAW, where there are a lot of links to deal with. I pop open the links I know, run searches in new tabs for the ones I need, then copy the whole bunch as references to paste into the top of my post.