Apparently I have lost the ability to do anything creative today so instead lets try this:
An episodic in-store 'event' project that united all the primary imagined worlds of ALL the OGL-Born OSR companies into one giant mega-adventure to be played weekly by people all over the globe using ANY of the those OSR systems in which the results of all of the efforts of these tiny groups are all reported and collated in some way to influence the final result. With content from ALL the major OSR bloggers and writers.
It would be a combination of the railroady in-store playalongs that WotC did for 4th ed, the giant event crossovers that Marvel and DC do where some giant fucking thing attacks the earth and everybodys book is about that for a month plus a shitload of publicity for the OSR in general.
The Giant Fucking Thing:
The Moons Dark Pavillions
The dark side of the moon is inhabited by an ancient empire of the Han Chinese who have merged with the shadow dimension, then without warning the moon begins to rotate, showing its dark face and the dark cities thereof, gigantic chains are lowered to the earth and roving shadow-cities are born where the touch the ground. Infiltrate or attack the cities or climb the chains and fight the moon.
Comets of the Crime God
The three comets holding the shattered fragments of the defeated God of Crime are meeting again in the night sky. As they grow closer to convergence criminals all over the world become more powerful, Empires and Governments invert, suddenly they are ruled from below. Social anarchy. The PC's are probably criminals, which explains their rapid levelling, but when it turns out that the Crime God intends to steal the sun and freeze the earth to death, will they be powerful enough to stop him?
Dead Lords of Jove
The ships of the Lich Lords Jove gather in the night sky. The solar system has been drained of resources, the Lich Captains need fresh crew, which means war on earth! Dead sorcerers from every period of earth history return in orbiting ships of bone and ice, they demand tribute and war! The PC's find a way to space to fight the threat, whilst dodging orbital fireballs and global megaconflict.
Like a Masks-Of-Nyarlathotep geographically separated but timetable-linked structure with semi-randomised conflicts and levelling points. A general structure decided centrally, both in its interacting narrative parts and its information architecture. Then separate briefs sent to each creative team.
Games Workshop used to do mass play events where people wold all play missions based on a particular battle and sent their results to the company and they would all be collated into one giant result.
Actually that would be insane for a mass-played RPG, even for this insanely conceived project.
XP couldn't be the same but you could have action-specific equivalents given in fractions of a level. I.e. reach this point and you advance 1/2 a level. Do this thing, kill this guy, steal this gem, and you advance 1/4 a level.
Monsters could be reduced to an ultra-simple stat line and minimal special rules. Magic items could be reduced to very simple test-only descriptions.
All you would need to do is persuade a bunch or tiny under-funded companies, each run by anarchistic weirdos, that it was a good idea and that they should combine funding and publicity for one gigantic unproven project.
But you might get good press from places like Boing Boing etc as the combination of small companies and global sandbox/modular yet-interacting gameplay and one giant story would sound pretty cool.
Really I just want to wipe those horrible 4th ed railroads from my mind and find an excuse to combine all good ORS blogs into one giant megathing that solves all game design, adventure structure and layout problems for ever.