This won't work. In Excel::Template, I am forced to load at runtime the rendering module I'm using, based on a flag passed in to the constructor. Spreadsheet::WriteExcel has a 7MB limit. Spreadsheet::WriteExcel::Big doesn't, but both depends on a number of other modules and (currently) has not been made to work with mod_perl. Your method will miss the fact that Excel::Template is an interface to Spreadsheet::WriteExcel and Spreadsheet::WriteExcel::Big.

It may be a good start, but would have to be modified by people knowledgable about the guts of various modules (like, say, the current maintainers).