By mid to lower level involvement are you implying that some guys are actually on the street selling to buyers at will like some of the street gangs (bloods,cryps)?
By "mid level" I mean at various wholesale levels. "Lower level," when it comes to the mob, would be selling to individual dealers themselves, not actually selling to customers on the street. For instance the mob is big into distributing ecstasy to individual dealers, who then distribute it in mob-controlled clubs. The only street-level drug operation involving the mob I've ever heard of was a Lucchese crack distribution ring in Brooklyn back in 1996. James Galione, a Lucchese soldier, oversaw the ring and his own dealers, as well as charged a "street tax" to unaffiliated dealers in the area.