Wifey made this for me tonight for dinner, with the only meat that should ever be in a Shepherd's pie... Lamb (the "Shep" part should give that away). It was based on a Gordon Ramsey (deconstructed) recipe linked below, but with a few changes. Mostly because she couldn't get the wine open, extra Worcestershire sauce and added ground Oregano. Turned out AWESOME.
Pearl onions have been added to my growing list of underrated foods.