<p>As @AndreSilva <a href="https://stats.meta.stackexchange.com/questions/1963/can-we-add-the-ability-to-sort-questions-based-on-the-number-of-up-votes-from-hi#comment5419_1963">notes</a>, this cannot be done within the SE ecosystem.  It is important that voting be anonymous.  As a result, who has voted on what cannot be accessed by anyone except the developers.  You cannot get this information either directly or indirectly from the SE data dump, for instance.  (For example, it is not possible to query and find out your <a href="https://meta.stackexchange.com/questions/84011/is-it-possible-to-know-how-many-competing-answers-i-upvoted">progress</a> towards the <a href="https://stats.stackexchange.com/help/badges/63/sportsmanship">sportsmanship badge</a>, because this would make it possible for someone else to figure out how you voted.)  If the system you suggest were to exist, it would be at least possible to narrow down who is voting on what.  </p>

<p>I'm not sure what you mean by a "high-karma user" exactly, but anyone whose <a href="https://stats.stackexchange.com/help/privileges/set-bounties">reputation is >75</a> can promote a particular thread by setting a <a href="https://stats.stackexchange.com/help/bounty">bounty</a>.  There are a variety of <a href="http://blog.stackoverflow.com/2011/09/bounty-reasons-and-post-notices/">reasons</a> related to your idea that can be cited, including to draw more attention to the question, to get a canonical answer, or to reward an outstanding answer.  Questions that have active bounties are listed on the <a href="https://stats.stackexchange.com/?tab=featured">featured tab</a> of the main page, and do get more attention.  You can also navigate to the user page of whomever's opinion you particularly respect and see what bounties they have offered in the past, by clicking on bounties -> offered.  We probably should encourage people to offer more bounties for questions and answers that they feel are especially noteworthy.  I'll admit I feel remiss for not doing this more often.  At present, the reigning champions seem to be <a href="https://stats.stackexchange.com/users/805/glen-b?tab=bounties">@Glen_b</a> and <a href="https://stats.stackexchange.com/users/930/chl?tab=bounties">@chl</a>.  </p>
