In an unusual flash of common sense, it suddenly occured to me that I could have my cake and eat it, too: I could get a large sub (the Adire Rava) and put it on the other side of the room, IF I ran a cable through the wall from the receiver to the sub. (If I tried to run a cable over the mantle of the intervening fireplace, I would be single again tomorrow.) This leads me to the following question: What type of cable should I use to connect the RCA jack wallplates that will intervene between the amp and sub? I don't want to spend more money than need be, but since I would like to get this right the first time, I would prefer to err on the side of better quality if need be. Any suggestions would be greatly appreciated!

I had recently picked up an RCA (the brand) rca cable, 30 foot from ebay for about $25.
With a copper centre and some general shielding being my only requirement in the cable, it was pretty cheap. Sure gave me alot of movability placing the sub around the room.

I hope you place a review on that Adire if it ever comes to be. I'm really interested in hearing about their sound.

Dan from Adire recommended the Cat Cable subwoofer interconnect to me. I got a 3m cable for $40 or so; you can get any length you'd like, and it's a real solid product at a great price.

I haven't received the Rava yet, but here's how I've arranged the wiring, after browsing some of the DIY cable sites:

1) I am using Belden 89259 coax for both in the in-wall and patch portions of the interconnect. This is the wire used in the much-vaunted Jon Risch DIY interconnect and in DIYCable's subwoofer interconnect kit.

2) The in-wall portion will terminate at either end at an inexpensive solder-type RCA jack from Parts Express, mounted in a standard wall plate.

3) I will use the remaining cable to make two patch cords, each terminating in Dayton Audio locking RCA plugs, also from Parts Express.

The cost for the cable and all parts (including wallplates, solder, and soldering iron) was less than $100. Now let's just hope some of my soldering skills have survived from my teenage days....

Randyman was a great help with the soldering info. We had some posts going back and forth on it not long ago.
Lead free really is the way to go but that is coming more from my professional background than anything.
SAVE THE EARTH, GO LEAD FREE!!