Our "banner" is basically a table that we have inserted into the template html.
Basically, there are a number of table rows, each with a different background color and a fixed height (using a blank.gif).
Think of it this way:
Row 1: Highlight Color
Row 2: Color Band
Row 3: Shadow Color
Row 4: Menu Row
Row 5: Highlight Color
Row 6: Color Band
Row 7: Shadow Color
Row 8: Banner Row, with left and right images
Row 9: Highlight Color
Row 10: Color Band
Row 11: Shadow Color
The easy way to get your Banner row to adjust for different screen resolutions is to insert a table in that row, have fixed widths for your left and right images, and then have the center cell stretch to accomodate the screen width (use a matching background)