Any reason why you can't use QStandardItemModel? in that case subclass QStyledItemDelegate and reimplement paint
void QStyledItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
Q_ASSERT(index.isValid());
QStyleOptionViewItem opt = option;
initStyleOption(&opt, index);
/////////////////////////////////////
// Set the background based on the content
if(index.data().toInt()==1)
opt.backgroundBrush = QBrush(Qt::red);
/////////////////////////////////////
const QWidget *widget = option.widget;
QStyle *style = widget ? widget->style() : QApplication::style();
style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, widget);
}
