RBS has history, making an early, well-received decision on a new chief executive when the incumbent's been worn down by the overload of complex work to revive the UK-bank most damaged by the 2008 crisis.So perhaps NAB's board and stakeholders can expect banker Ross McEwan to rock up to his new Sydney digs sooner than November, or April, or whenever it is that NAB's board have said they believe the current RBS CEO might actually start.Then-Royal Bank of Scotland chief executive Stephen Hester had his change in circumstances - "forced out" was the media meme at the time - announced in early June 2013.By October of that year, Ross McEwan (with less than a year under his belt as head of the RBS retail bank) found himself promoted into one of the toughest jobs in global banking.On Friday, the day NAB announced McEwan as their CEO in waiting, Bloomberg published an analysis of the RBS CEO succession."State-owned RBS has been searching for McEwan's successor as chief executive officer for more than a year," the news wire wrote of a prudent but possibly pressing piece of work.Alison Rose, CEO of Commercial and Private Banking at RBS since February 2014 (and now also deputy CEO of NatWest Holdings), is the internal favourite. Some banking analysts are predicting RBS will name Rose, 49, as McEwan's successor as early as 2 August (to coincide with the bank's half year results).  Given her insider experience, Rose will need no lengthy handover from her boss. It's easy to surmise she and her chair may prefer McEwan moved on in short order.If any of this is on the money it may well mean the RBS board will be in a position to greenlight McEwan's starting date much sooner than outlined by NAB on Friday.Might he be permitted to start at NAB by early September, tasking McEwan with presenting the full-year results?The comparative strength in NAB's share price yesterday - up 5 cents to $27.56 on a down day for the market and other big banks - shows the market buying into the McEwan value and turnaround story.