Frontend Bug Reporting plugin for Website Beta Tester

Bugherd is one of the best out there, and you can embed it by including some javascript to your website. Although it might be wise to build what you want yourself. What you described shouldn't be that hard to build, if you keep it simple.

You can use Saber Feedback (was BugMuncher) or Diigo. These can be used for reporting the bugs directly from the Web Page. If you need a complex stuff..!!

Google feedback is best choice i believe. It's actually a feedback tool currently integrated into Google+. Once you click it, it pops up a little toolbox that allows you to "highlight the problem".Rather than asking for a screenshot or even using any terminology like that, it just talks about highlighting the problem* and blacking out personal info. Then it asks you to add a comment, preview (using a generated screenshot of the page) and send. Its REALLY SIMPLE, Good to use and never makes thing more complex. Typical Google stuff..!!

Usersnap solves your problem. It delivers visual feedback (screenshot + annotations) and integrates with your existing bug tracker (Have a look at the list here: http://usersnap.com/doc/connect).

It's a small widget which is added to your web page in minutes (just a few lines of Javascript):