why not?
though I would make your report head a page header as there will multiple orders in your report, not just 1.
same for the report footer, it would probably be a group footer.
I can see a report footer for the total, I would think that it would a separate page...because I would think that you would want to total up each invoice individually and display that, and then dispaly the total of all the invoices.
The subreport would need to use a shared variable to return the tax information to the report to be included in the totals, but other than that, this sounds like a simple straight forward report.