Recreational pharmaceuticals by genetic engineering

I know this is off-topic for the list... But why hasn't some cleaver graduate student engineered a common mold or yeast to yield easily extracted (or directly ingestible) common recreational pharmaceuticals? Ideally it would be a perpetual source, like sour dough starter, and easily cultured. Once distributed to the street it would be impossible to stop or track (since no controlled chemicals would be required for production). --$teve