Photo by AlbinoFlea It’s not hard to find someone who’s frustrated that District residents still don’t have full voting rights. But no one is as willing to act on that frustration as Doug Sloan, it seems. Sloan, who is challenging D.C. Del. Eleanor Holmes Norton to be the District’s non-voting representative, proposed a radical idea today to get Congress’ attention — block the bridges carrying commuters in from Virginia. “If you really want to…