From Neal Applebaum:

I think it would be helpful if Atlassian could publish some guide to customizing the Excel output, along the lines of what you put above. For example, for every Excel output I have to:
1) remove the logo
2) remove the opening lines (1-6)
3) remove the closing Generated by summary
4) Change all cells to vertical alignment - top
5) Change all cells to autofit row
6) Change page setup for paper size, margins, custom footer
etc.

Not everyone will want the same defaults, I understand, but it would help if I could customize my own installation the way our site wants it. Now, I've figured out how to accomplish items 1-3 by simply removing some code from navigator-excel-current.jsp (lines 50-69, 105). If I could somehow have the other preferences automatically be the default in the Excel file, that would be great. I think there are many users who rely on printed or electronic spreadsheets for status meetings.