Sadly it may end up being a reference template only. Still can help as it would be a good guide.
You could copy excel sheet then edit each reportlet items in manage menu. You can then change Reference report suite and then associated segments to point to new one.
2 Caveats to watch out for.
1 If any unique variables exist in first report builder doc. associated to 1st report suite
2 If any segments are used in first report builder doc. associated to 1st report suite
They need to be available in 2nd sites report suite or else it wont be an exact match.
GLTU