Below is the pitch as taken from Mieville's tumblr. It's hardly surprising that it got rejected considering it's socialist leanings and casting one of the comics' world's established Heroes as a villain, but it's a great pity. I for one would have been delighted to read it.

A six-issue comic, with a view to introducing a new hero into an existing canon.

The economic crisis bites. Flinton, MI, was built on industry, and the industry’s gone, since by far the city’s dominant company took the stimulus cheque, attacked wages, outsourced more and more, then finally all, R&D and production overseas. Flinton, like so many other towns, is dying.

An extraordinary figure in bizarre makeshift power armour the colours of rust and hazard-warning yellow has appeared, fighting burglars, thieves, drug-dealers, graffiti-taggers. Flashback: he’s Dan, an ex-worker in one of the high-tech heavy defence plants, horrified at the social breakdown, going through the many scrapheaps of the town and cobbling together his suit from industrial junk, trying to save his home.

Dan smashes up a crack house, but while most of those within run, one stays and jeers at him, calls him a bully. Dan knows her: Louise was the union rep at his factory. He’s ashamed: he always liked her. They get talking. ‘You really want to do right by Flinton?’ Louise says eventually. ‘By all the other Flintons? Then quit messing with symptoms. It’s time to take down the real villain.’

Louise has contacts. They gather together a group of laid-off workers, from all the fields and departments of the now-dead industry, who with their combined expertise add weapons, flight capability, computers to the armour. Over Dan’s initial resistance, Louise even insists they contact some of the overseas workers where the plants have been relocated, to get up-to-date information, technology, and help, because, Louise insists, they’re on the same side. They make the suit vastly more powerful.

Dan knows how to fight, but that isn’t enough. They put controls in the suit connected to a central hub in Flinton, into which they can log, so Dan will be in constant touch with the others, who can take control of different aspects of the system as necessary: so the other scrappers can help fight, the veteran who was once a sniper can aim the weapons, the one with a pilot’s licence can fly it, the techie can patch into data systems, and so on, and they can all strategise together. A single-bodied union. A collective superhero.

They’re almost ready. They’re preparing to finish the cosmetic upgrade on the prototype suit: it still looks like junk. But Dan and Louise stop them.

‘No,’ Dan says. ‘We need a symbol.’

‘Capitalists are a superstitious cowardly lot,’ Louise says. ‘This fucker put our town out with the trash, threw us on the scrap heap. Well, the scrap heap’s got up, and it’s coming for him.’

The crew take their places at the controls. Dan puts on the battered welding helmet that disguises his identity and, in a burst of rust, launches into the sky for New York, to face down the sociopathic authoritarian fascist arms-dealing corporate billionaire responsible for so many countless deaths, in the US and around the world: Tony fucking Stark.

Dan: ‘Get ready for payback, Iron Man. We are Scrap Iron Man.’