Packing Slip for Ubercart Customers?

Is there a way (a module perhaps) where Ubercart customer info creates a configurable packing slip or letter?  I would like to print a standard letter with each sale, together with an envelope. 

I gerrymandered such a system on D6 by adding additional pages to the printable invoice, but D7 and Uber3 seem to do things differently to how they used to.  Has anyone found a simple way to do this on D7?  Any help appreciated.

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