If you want to add coloring and formulas, you need to alter the Java code of the Excel Exporter module. Indeed the Apache POI has all functions to properly implement this; it will be hard to make a generic implementation for this, using a template or so. A more specific implementation to your use case is definitely doable by altering the Java code.
Yes, you can generate an excel by using the Excel-exporter, but it will not have any formula's or colors. As a workaround, you can have a second Excel containing the formula's and colors and have this second Excel have a lot of cell-references to the one you download, but this gets sluggish quickly and is therefore not advisable.
What does a Pissed Of Iraqi (POI) have to do with all this? Or Point of Interest? Apache POI?