iphone to computer headphone/mic adapter

I've searched the archives and googled till I'm blue in the face but no one seems to make a 2x 2.5mm Female Mic/Headphone to 3.5mm Male iPhone Y adapter. Earbuds bother me after a very short while and the ambient noise in my office is a nusiance. I have an excellent pair of headphones with a boom mic attached that is also of very good quality (much better than the dangling mic's that bounce off your shirt, etc.) Unfortunately most, if not all of these setups are made for computers and have separate audio and mic 2.5mm Male connectors. What is needed is a Y connector to receive the two signals paths with a single 3.5mm Male iPhone connector. In my own searches there seems to be a zillion or so other individuals looking for the same thing. Sounds like a business opportunity to me but anyway, if anyone has found such a beast I would appreciate a link as I've not been able to find one.