If you want to, you can ship them to me and I'll do it. All you have to do is pay for shipping and seven dollars for work done and the jack. If you want to take this option PM Me.
EDIT(what you need to do this)
Tools
-Solder iron (preferably 60 watt, but you can use as low as 15)(25 is good if you're just starting out)
-Solder( 60/40 is ok, 63-37 is preferable, Silver solder has a higher melting point so don't use it if you're just starting to solder. It's also more expensive)
-Pliers. No one wants to burn themselves with a soldering iron. Use the pliers to hold the wire while you're soldering to sink heat
-3.5mm jack. Whichever one you want
END EDIT
All you have to do is replace the plug. You don't need a full re-cable. That's just silly. Unless your cable has multiple stress breaks, which I doubt. Anyway how to do it:
1) Go buy yourself a good plug. Neutrik makes great 3.5mm plugs and they cost only a few bucks. Problem is, the Neutrik 3.5mm plugs might be too thin for that thick cable you have on your Denon AHD2000's. You might need to get a quarter inch jack or go buy a larger 3.5mm jack like Canare F12. If you really don't want to pay outrageous prices for shipping online, just stop by your local Radio Shack and pick up a gold plated jack from there for $4.49 plus tax. (Cheapest non gold plated is $4.19 for two). Really, the jack is all up to you and what you want.
2)Now, you need to be able to solder. Identify the ground wire for the headphones. These are usually copper colored while the left and right lines are green and red respectively. I don't know for sure, but these Denons probably have enamel coated thin wires so that they can be placed in bunches to make the wires flexible. If they have enamel coated wire, you need to use your solder iron to burn off the enamel coat.
3) Take your jack and remove the cover. Make sure the wire fits through the hole. If not, take a knife and widen the hole until you can fit your wire. If you don't want to use a knife, use the appropriate sized drill bit. (Plastic is easiest to work with if you have an exceptionally large wire.
4) Solder the leads to the correct terminals.
On Radio-Shack Jacks, the largest solder terminal is the ground. The smallest solder terminal is for the left channel while the intermediately sized solder terminal is the right channel. Remember to pre-heat your soldering surfaces with the soldering iron (both wire and soldering tabs) so that you can flow the solder and it will make a solid connection.
5) Slide the cover down the wire and re-screw it back onto the base.
You're done!
How to burn enamel off of wires
1) Twist each separate lead into a tight bunch of wires. As in twist the ground, left and right leads into a neatly twisted bundle of little wires.
2)Take your soldering iron and heat your first lead. Out of habit, I start on the ground first, then move to the right lead and then the left lead.
3) Once you've heated the lead for a minute or so, keep the tip of your solder iron on the wire and slowly feed the solder onto the tip of the wire. The heated wire will flow the solder onto it and keep feeding until you have a "large" ball of solder. (large = 1 to 2 mm in size).
4) Use the solder tip in order to move the solder around to make sure it makes contact with all the surface area of that lead. Do this until you know that the enamel has been burned off.
5) Remove the excess solder.
6) Repeat for each lead.
