Not sure how well that'd work, maybe if you spliced and soldered it'd work, but I'm not entirely sure because it gets a tad confusing when you have bundles of wires. If you're good at soldering give it a try but don't blame me if you end up with two non-working headphones.

However, there are a few adapters on the market which let you just plug in your own headphones and still have headphone controls. This one by Griffin works with iPhone as well as iPods, but this cheaper sleeker one by Belkin works with all iPod models and looks rather nice.

Depending on your headphone/earbud style i have seen people who have de-soldered the OEM buds and just used the cables on a replacement set of buds. YMMV. but i know one guy that put some sony in-ear style buds on the Apple cables. he was a decent solder technician, so again, you may have some trouble if you aren't too good at fine-pitch solder work. but it can be done. I've replaced the cables on a few sets of BOSE headsets that the cables had been pinched or not long/too short for use. so i can vouch for doing it. i have thought about doing the same thing, but don't have a set of headphones that i've wanted to try it with as of yet.

good luck to you. and if you are willing to plunk down the green for it, the Apple In-Ear Headphones are actually quite good. I have a set and they sound marvelous. They have the control on them