I've been thinking about a module that would export to Postcript (which are easily convertible to PDF) that would do just that.
I was thinking about a generic "report generator" that would be able to take templated variables and insert them in places in the Postcript output. Then an invoicing module that would use that service package.
I've never done anything with creating postcript files, so the biggest barrier for me would be that learning curve.
Anyone familiar with what it takes to create postscript?
-Roberto