Well I picked up a refurbed CMD6 to replace my CMD4a. I really wanted the usb control for the Ipod. I new going in that my three existing wired remotes would need an adapter cable to work with the new deck. Here's what I learned when trying to track down a CCUMRA1 cable:
They were only available for a couple of years and have been discontinued. I found a wholesaler in Canada that still had some inventory and he gave me contact information for one of his dealers that I could order through. It ended up costing $68 but that is still a lot cheaper than replacing a single remote much less three. I did bite the bullet and orderred a new remote for the driver. The y-cable, 25' cable and remote were more than the refurbed CMD6. Here's the contact information for future reference:
The guy's name was Idan
email address: firstname.lastname@example.org
So if you think you're going to need one of these you better get on the ball.