McEwens from around the world have chosen the perhaps unlikely setting of a Clydebank hotel for a unique "family convention" where they will look at securing a head.
At present the leading contender is Sir John McEwen, a 48-year-old Berwickshire-based baronet who is a freelance journalist.
But the McEwen clan, which the takes in a long list of surnames as variants, could actually end up with two chiefs amid moves to separate the clan into two distinct clans - the Ewings and McEwens.
The Clan Ewen Society and the Ewing Family Association have unanimously supported a motion that "clans Ewing and MacEwen be recognised as distinct clans".
Herefordshire-based historian and writer John Thor Ewing is backed to become "commander for clan Ewing".
Mr Ewing said he would be attending the family convention -taking place next month at the Beardmore Hotel - to clear matters up.
The last McEwen chief was Swene McEwen, who died in 1492 and members of the clan society see themselves as "probably the largest and most important chiefless clan".
Matters came to a head five years ago for the society at The Gathering, a major meeting held at the Scottish Parliament in 2009.
It said: "While there have been efforts to secure us a chief since at least the 1950s, it became especially clear at The Gathering in Edinburgh, 2009, that clans without chiefs were firmly in the second rank. We all determined then that a chief of the McEwen clan had to be found."
The society engaged Hugh Peskett, a renowned genealogist, and following his work the Lord Lyon organised a family convention to elect a chief or, at least, a commander of the clan.
Sir John McEwen of Marchmont and Bardrochat at present is the only candidate. A journalist who formerly wrote obituaries for the Daily Telegraph, he lives near Duns.
The baronetcy was created for his grandfather, the Conservative MP John McEwen, who was Under-Secretary of State for Scotland from 1939 to 1940.
Sir John said of clanship: "When we walked up the Royal Mile in Edinburgh in 2009, it seemed real. It mattered. It was also clear that the clans with chiefs were in a different category.
"I think the clans can make a contribution in the new Scotland. It is fun, but it also helps provide identity. We are not living in the past. We are honouring the past."
There is a long list of surnames as variants of the clan name McEwan/MacEwen - from Eunson and Ewing to McOwen and even Quinn.
There are said to have been at least three McEwen families which existed before 1600, each with its own history.
The clan society says that probably the oldest of the McEwen/MacEwen clans was descended from a branch of the Bissets, a Scottish family of Norman origin, which settled in Antrim, Ulster, and took the name of MacEwen from their chief John (Eoin) Bissett in the 13th century. In Ireland they are most often known as McKeowns.
The name MacEwen was also borne by prominent members of Clan MacPherson, after their founder Ewen Ban MacPherson.
Meanwhile, the medieval Clan Ewen of Otter had lands on the shores of Loch Fyne. This clan was dispossessed at the death of the fourth chief Swene in 1493, when the core of the clan seems to have moved to the lands of Lennox on the shores of Loch Lomond.
Mr Ewing says the evidence clearly points to the Ewings being their descendants.
The remains of MacEwen castle are on a rocky point on the coast of Loch Fyne. In 1995 a cairn was erected among the ruins.