I saw one of Hogsy's cooks with potato skins and they looked awesome, so I thought I would give them a go. These turn out really good. I would have needed to add coals during the cook but didn't, so they ended up in the oven after they were loaded up with the fixings.
Here's the basics:
fire up the grill to about 400
a little canola oil and salt on the skins
cook for about 40 minutes until tender
let potatos cool down for a bit
slice potatoes in half and scoop out the insides
coat inside and outside of potato with a mixture of melted butter and a little bacon fat or oil
back on the grill for maybe 5-10 minutes to crisp up skin
take back off the grill and load them up with cheese, bacon, green onions - then back on the grill for another 5-10 minutes and you're done.