I'm not sure if your question is only about the old N95 headset or remote controlling ones in general. However, I have a bluetooth stereo HS from Plantronics and it's been working fine so far, at least regarding RC functionality. "Next track" function used to not work with Mediabox, but it does with the newest version.
Also, I believe there's a thread somewhere here teaching how to use the HS included with the N900 to manipulate the Media Player...