Robert Plant told the crowd it’s been a long time since he’s rock ‘n’ rolled – but will it be the last? By all reports – and by the snippets that have been put online – Plant, Jimmy Page, John Paul Jones and Jason Bonham were rehearsed, ballsy and spectacular.

It might be the last time anyone will ever see them onstage – Plant has said he’s not feeling a tour, although Page and Jones were amenable (or has Plant hinted at a tour? Media reports vary and, basically, it’s one big kerfuffle). Ultimately, there could be factors that will motivate them and it sure ain’t money – they’ve seen plenty of that and would certainly see more. It could come down to the following:

“With a synergy like this going on, it would be an act of cosmic perversity to stop now,” said Pete Paphides of The Times of London.

“They sound awesomely tight,” Alexis Petridis wrote in the Guardian. David Cheal of the Daily Telegraph said the band’s “familiar old sinew and swagger were still there.”

So, for grins and giggles, let’s speculate:

There are two promotion companies that easily would have the ability to launch Zep again – Live Nation and AEG. Of those, AEG was clearly present at the show, with AEG Live President Randy Phillips and, according to sources, AEG President Tim Leiweke on hand. Those aren’t the kind of folks who fly from Los Angeles to London to just do some headbanging.

In fact, Phillips was said to have made an offer as soon as the show closed. Meanwhile, Gary Arnold of Best Buy – which sponsors the Police tour – was on hand.

Of course, the Zeppelin camp has said touring is just wild speculation – which is many times code for “we’re touring but wait for the official press conference.” And there are plenty of ways to tour other than traditionally. It’s always possible to take up residencies in major cities and let the audiences come to them.

If there is a tour, it won’t likely be next spring or summer. Sources say Plant is committed to tour with Alison Krauss, promoting their collaborative Raising Sand, between June and August. There’s always an earlier time frame – but, unless the tour has been in the works for months, large arenas are already committed to sporting events or concerts.

Which leaves the fall. Or nothing at all.