Will nineteenth century ideas on banking leap to the fore at the Brisbane G20 summit in November?Will the leverage ratio eclipse the Basel risk-weighted ratios and the rest of the global regulatory circus?There are strong US and European connections adding their voices to the clamour for a leverage ratio.Six per cent and seven per cent are on some people's lips and in the post GFC debate this has ranged to more than ten per cent.Australian banks are below this level. ANZ, for instance, operates at half this ratio.The simplicity of the ratio seems to be its selling point, along with acting as a decisive brake on a once unfettered industry.All the Cairns communiqués had a tone of "business as usual" and "progress made against work programs" about them.APRA is turning up its own talk of a leverage ratio, a number that may soon be deafening.Behind the IS smokescreen, will there be G20 reform of banking?