Component {
    id: folderDelegateComponent
    WhatEver { }
}
Component {
    id: recordDelegateComponent
    WhatEver { }
}

delegate: BackgroundItem { // or ListItem, whichever you need
    Loader {
    //set size etc.. to fill the parent or whatever you need

        sourceComponent: switch(model.data.type)
                 {
                   case "folder":
                    return folderDelegateComponent;
                   case "record":
                    return recordDelegateComponent;
                   default:
                    return errorComponent; // maybe?
                 }
    }
}