The lack of keyboard shortcuts for Chrome has been frustrating for me, too. Figured out an easy way to trigger these bookmarklets in Chrome without needing a 3rd party extension by adding them to the search engines. Wrote up a quick post on it, hope you find it useful (composed in nvALT, of course). How to Make Javascript Bookmarklet Shortcuts in Google Chrome
Firefox solution:
<ol>
<li>Drag bookmarklet to Bookmark Toolbar. </li>
<li>Right click (or two-finger click) the bookmarklet and select Properties from the context menu. </li>
<li>Type a keyword of your own choosing in the Keyword field. (I chose sf). </li>
<li>When you need to use it, hit [command] + L (i.e., focus address bar) + sf + [return]. </li>
</ol>
Hey, it could be shorter, but it avoids the mouse/trackpad and it works. But the pattern could be easily shortened with Keyboard Maestro, QuicKeys, etc.
Nota bene: I tested this with FirefoxAurora. It may not function properly in vanilla Firefox.