Ebert Beeman is an elected Libertarian-Republican County Commissioner in Erie, Pennsylvania. As Ballot Access News points out below, Beeman was elected as a Republican, but the local Republicans dislike him, immensley, cause of his maverick explictly name-names reputation on local county contracts. The GOP disowned him. Beeman officially joined the Libertarian Party. But he is still technically a Republican.

Now, the Libertarian Party has nominated him to run for Congress.

From Ballot Access News:

Beeman was elected to the Erie County Council, 6th district, in a partisan election in November 2009, as a Republican. However, he had been a registered Libertarian as recently as May 2009. In the 2009 general election, the Republican Party had opposed Beeman even though he was the Republican nominee. Beeman won anyway, with only 32.14% of the vote. The November 2009 vote was Republican (Beeman) 2,132 votes; Democratic 1,924; write-ins 1,624; independent Steven Porter 773 votes; and Green Party 180 votes. Beeman is an interesting person; see this news story from October 2009 describing him.

Note - similarly, New York City Councilman Dan Halloran (upper Queens), is also an elected Libertarian-Republican, with dual affiliation.