Provide spanning in QTreeView

QTableView has a very nice spanning feature which would be nice to have in QTreeView.

It is understandable that row spanning would be difficult to implement in a QTreeView, given that some rows may have children, however, spanning across columns should be much simpler and would be very useful.

For example, if a tree has 20 columns, it might be necessary to span column 10 through to 20.

The current spanning only allows the first column to span the width of the entire tree. This is not very flexible.

A function/method like setText(int column, const QString &text, int > span = 1) would be very nice.
(The same thing would be very usable for QTableWidget for the functions setItem and setCellWidget just like in QGridLayouts' addWidget).