Just so we have a solid foundation on this problem,,
1) The noise has gotten louder from when you first purchased this bike. That is without question, the noise has gotten louder.
2) Have you ridden any other bikes to absolutely confirm that what you hear is abnormal. When I say "any other bikes", I mean post 2007 twin cam 96 engines.
If the answer to Both questions is YES then the next step I would take is to remove the oil sending unit and install my own quality oil pressure gauge and measure the oil pressure when the engine is HOT at both idle and 2500 RPM.
I don't care what the oil light does and I do not care what the built in gauge says. Install a quality gauge and measure the oil pressure.