Would love to be able to search for certain keywords, Ctrl+A or Shift+select a few results and delete them all at once (like in Firefox). At the moment all Opera is allowing me to do is to either a) delete everything or b) delete results one by one... which is crazy tedious.

You know Opera has a quick search function that does exactly that with even less keyboard use, right?

http://help.opera.com/Windows/9.51/en/search.html