The combined authority proposed six months ago by four Black Country councils with Birmingham has now enlisted the influential support of Coventry's ruling Labour group.
Even Conservative-controlled Solihull, by far the most reluctant potential partner, is set to debate a recommendation that it should join in as well.
A Midlands Powerhouse in which Birmingham Airport, the National Exhibition Centre and a potential High-Speed rail station were conspicuous by their absence would be something of a nonsense.
The prize being held out by the chancellor, George Osborne, is the unprecedented bumper bundle of political and spending powers worth billions of pounds, along the lines of those already being handed out to councils in and around Manchester.
With it would come extra clout for local decision-makers in important areas including housing, transport, planning and skills.
But in return they may yet have to stomach the idea of a directly-elected "metro mayor".
In the face of overwhelming evidence that such a new-style regional boss is generally unwanted here, not least by the council leaders themselves, Mr Osborne is adamant that the new role is a "pre-requisite".
No less controversial is his insistence that the "devolution revolution" is for the cities but not for their surrounding counties.
Stand by for yet another war of words - Conservative leaders of neighbouring shire counties, including Adrian Hardman in Worcestershire - waste no time in reminding us that our non-metropolitan areas produce more for the UK economy than those much-vaunted major cities.
All this talk about the "Northern Powerhouse" seems to be concentrating minds wonderfully here in the West Midlands.