Web Forms - Is there a way to create a subform or tabular view?

We have a need to support a dynamic header -< detail form where the detail is a dynamic list of items.  Similar to a purchase order with many order lines.

We want to repopulate the header and the detail with what we know about the recipient and let them fill in the blanks for missing information in each subform.  This could be a grid-like view or <Previous  |  Next > type of control for each of the lines (probably easier for a mobile app).

I thought I could use Agreement Template Builder template with a dynamic table, but ATB templates are not supported.