Are there any low time lucky CPL holders who operate as PIC on medium or heavy jets?
There have been periods of time in the past (and I think at present as well) where a lack of experienced pilots meant airlines had to resort to hiring CPL's as SIC's on turboprop and some regional jets. I know that American Eagle did that for a while -- they used to call them the 500 hour wonders. Some were hired with even less time if they showed exceptional skills. 

However, to log PIC time in an aircraft that requires an ATP ticket, you have to have the ticket. Sole manipulator of the controls is not enough for a CPL to log the time as PIC on those aircraft.