I am having a similar problem coding this email for Outlook 2010 (of course). The email is fine in most client but the width of the text ares is bigger than it should be. No matter what CSS, or html width I apply Outlook is rendering the width of the cell wider than it should be.
I think the problem is with your colspans and rowspans. I recommend ditching them completely and layering tables instead. This will give you something similar to CSS.
Create one "container" table that is 1 column by 3 rows. Then create a new table in the top row for the header, one table in center for the body, and one in the bottom for a footer.
Then if you need to break things down even further, keep adding tables.
Good luck!