There's nothing special about SACD/DVD-A cables. They're simply audio interconnects, and you need six of them. You can grab three pair of any cheap cable and that'll do the trick.

Though how long do you need? I see that Blue Jeans 6 channel cables are about $78 for a three foot length. You hve to get up to 9' before they're $100. It only has to reach from your DVD player to your receiver, no?