I was thinking of the feasibility of running a game using / allowing the use of ALL of the OSR rules available.
I know Zak has the Flailsnail Concord or some such, allowing the use of characters from different rule sets and campaigns in Constacon sessions with some conversion if necessary, but I'm thinking more like a regular, coherent campaign that allows for the use of multiple OSR RPG rules by the players.
For example, John wants to play a fighter from Labyrinth Lord, Advanced Edition Characters, Tom wants to play a magic-user from Basic Fantasy RPG, Cindy wants to grab a cleric from Swords & Wizardry Complete and Adam isn't sure what class he wants to play, but he knows he wants to use the Adventurer Conqueror King Systems for his.
I'm figuring except for AC, everything should work fairly well. AC would need to be converted to one of the systems in use.
As long as no one becomes a rules lawyer over minor hiccups, the DM should be able to hand wave any inconsistencies.