AA, thanks alot for the info on the Twisted Pairs cable! I just ordered one from CJ's Audio. I asked CJ's to find out if they will make a custom stereo-mini-to-stereo-mini, and if they do, I'll pass on that info.
If anyone reading this is thinking of ordering any of this stuff, it might help if I explain my own setup, because the physical layout of the units and the cable plug orientation can make a difference. If you don't care, just skip the rest.
I need to connect a WM-D6C to my preamp (this means two dual runs for the tape monitor loop), and a PDCP as well. The line-in and line-out of both of these units requires 1/8" mini phone plugs. The WM-D6C is an excellent tape deck on it's own merit, and I can use it at home to record directly from CD or my turntable, or dub from my Nakamichi tape deck. Given the physical layout of the equipment, side by side, I need straight-in plugs, not the right-angle plugs, and the better cable is often thicker and less compliant, putting more pressure on the portable unit, and the right-angle plug cable tends to "spring up" in the air, especially if it's not exactly the right length. Headroom's Straightwire cable is just not very flexible, with the two RCA-ended runs going side by side into the miniplug. While the RS is much more flexible, it doesn't seem too well shielded and I'm willing to believe it doesn't sound as good as the other stuff -- and it is very long. The right-angle plugs are nice if they're used for connecting portables carried in a bag, but that's not how I use them -- most of the time the portables are sitting away from my main setup, on a desk with my computer, connected to headphones or my Monsoon desktop speakers. I also need excellent RFI protection (I'm within sight of several radio broadcast towers) so well-shielded cable is a must.
So I'm taking the path of least resistance (no pun intended) and going for the consistent use of relatively inexpensive but decent sounding cabling. I'm duplicating my other system cables (all Straightwire Chorus) and using RS gold-plated adapters to connect to the WM-D6C. The Chorus is all I'm willing to spring for, given that I need connect many units. But I'm going splurge and get that one Twisted Pair to connect the PDCP.