Hi Nick
I was reading about making some XLR>RCA adapters today, and came across this over at diycable.com:
http://www.diycable.com/main/product_info.php?cPath=89_117_122&products_id=609If you want even cheaper, mouser has a pretty good selection of raw components. Switchcraft, etc. Cardas IC cable is some of the best quality raw copper wire you can buy, $7/ft from diycable. Shielded single twisted pair is all you need, metal quality and insulation have a bearing on sound, but it's all what you wanna pay. I'm sure mouser has el cheapo wire too.
I have belden/Canare ICs I bought assembled from Blue Jeans Cable. The RCA connectrs are really nice, but I don;t know how they are for sound quality, never did any experiments. They are great quality, feel good, and extra foot added to the 1 meter for free, But they are a little rolled off on the top and mids are slightly dimmed. But this is in comparison to great wires like Grover S. I still use them on tuner, and I love the sound of them. It is 1505 coax for wire. The Cardas might be a little more transparent, but that's just a guess.
I have used Switchcraft parts before for power applications, they are really awesome quality parts. The contacts are high copper alloy, but plated nickel, some people think that is a high end faux pas. They are cheap so might be worth a try anyway for your purpose.
Good luck
Rich