The tax and fuel is normally the same for all classes - the only major variant that I'm aware of is the UK where, until some time in 2009 (when the tax structure is changed) it costs twice as much to depart in any class above economy as it does in economy.

The ticket I quoted above is an AONE3 ex-MNL bought from AA. The base price was US$8494, and the taxes were $589.40. The routing is:
MNL-xHKG-JFK-SFO-xDFW-ANC-DFW-xSEA-LHR-DXB-LHR-HEL-CDG-HKG-KIX-xHKG-MNL