RCA to 25-bit

I want to connect a standard two-channel source (e.g. left and right RCA) to a 25-bit 6-channel input on the back of a sunfire theatre grand mkII. So far, the only company I've found who makes a cable is monster (a $90 cable that has 6 RCAs on one end and the 25-bit on the other end). Does anyone know if another company makes the same thing, using better interconnect cabling? Or if there's a company that makes an adapter to plug two rca cables into a 25-bit? I don't think this cable will do it for me, but I'd like to pursue this method of interconnection...
Is it really a 25bit(!) connector or a 25pin connector? I suspect the latter since there's no A/D converter in the cable. As for the $90, that's not too expensive for such a complex device but you can build a 2 (or more) channel equivalent more cheaply.

Just buy a 25pin connector and 2 coax interconnects at Radio Shack. Cut off one end of each coax and solder the leads to the appropriate pins on the 25pin connector. I assume that the connection info is in the Sunfire docs.
yes, i meant 25 pin. looks like the printer connection on the back of a cpu. thanks for the advice kr4. i'm actually not looking to do it cheaper than $90, i'm looking for cabling that's higher quality than the monster.
Why would you want to put a two channel source into the multi-channel input on your processor? This doesn't make any sense. Just hook up the analog stereo pair to one of the normal stereo inputs. The multi-channel input is for analog sources that output 5.1 (like DVD players with built in decoders or separate surround processors).
All right, all right, I'll explain. My processor (the sunfire) does not have an analog pass-through, and it's DAC's are not as good as the DAC in my CD source. As an alternative to using both the stereo preamp for CD, and plugging the sunfire into one of the stereo preamp's inputs, I wanted to use what the sunfire has as a version of an analog pass-through (i.e. the 5.1 input). So, I need a good cable that goes rca to 25 pin. I know it's a weird way of doing things, but I like to explore alternatives...

SOOOO, if anyone knows another company that makes such a cable, please let me know.