Warning: Answers to this question will be largely opinion based.
One problem that I see with creating one huge complex table is adaptability: what if you ever want to start grouping cells, collapsing/expanding sections, styling, enable/disable whole days, etc? Sure you could do this by hiding table cells and tracking which cells are headers and such but this approach will be missing many of the benefits that predefined controls provide.
You might want to consider subdividing your table into hierarchy of "panels": the top level panel is one row: your left-most static panel and then one panel per day; your next level is, within each day, you have a table with one column, the top row is your values panel, then your parameters panel, then your products panel. Finally, in each of those you have a "regular" table.
The actual Qt widgets you would use: one or more of QtGridLayout, QtBoxLayout, QtHBoxLayout, QtVBoxLayout, and maybe QtStackedLayout. See http://qt-project.org/doc/qt-4.8/layout.html for examples.