Cardas used to offer a 10 AWG 3 unshielded in wall product @ approx $17. per foot but it is listed as no longer available by their dealer Cableco.
 

JPS Labs also offers an in wall product with 2 10ga power leads + one 12ga ground lead

Beldon has their 83803 12 AWG 3 with a both a foil & a braided shield 

Food for thought

Dedicated 20 amp circuit - Electrician laughed!

I brought my electrician out to my house today to show him where I would like to install a dedicated 20a circuit for my system.  He laughed and said that's the stupidest thing he's heard and laughs when people talk about it.  It said, if you're going to do it, you have to have it separately grounded (shoving a new 8 foot rod into the ground) but even then, he sees no way there can be an audible improvement.

Now, he's not just an electrician though. He rebuilds tube amps on the side and tears apart amps and such all the time so he's quite well versed in audio electronics and how they operate.

He basically said anyone who thinks they hear a difference is fooling themselves.  

Personally, I'm still not sure, I'm no engineer, my room's not perfect, and I can't spend hours on end critical listening...  But, he does kinda pull me farther to the "snake oil" side and the "suggestive hearing" side (aka, you hear an improvement because you want to hear it).

I'm not taking a side here but I thought it was interesting how definitive he was that this not only WILL not make a difference but ALMOST CANNOT make a difference. 

I brought my electrician out to my house today to show him where I would like to install a dedicated 20a circuit for my system.  He laughed and said that's the stupidest thing he's heard and laughs when people talk about it.  It said, if you're going to do it, you have to have it separately grounded (shoving a new 8 foot rod into the ground) but even then, he sees no way there can be an audible improvement.

Now, he's not just an electrician though. He rebuilds tube amps on the side and tears apart amps and such all the time so he's quite well versed in audio electronics and how they operate.

He basically said anyone who thinks they hear a difference is fooling themselves.  

He sounds trustworthy so far.

Personally, I'm still not sure, I'm no engineer, my room's not perfect,

Then I would trust an engineer.
 

I'm not taking a side here but I thought it was interesting how definitive he was that this not only WILL not make a difference but ALMOST CANNOT make a difference. 

If we start with, say, Benjamin Franklin, and go through Chas. Augustine Coloumb, Faraday, Maxwell, etc… we pretty much end up with the basis for all electrical theory that is rooted in science.
The other theories are rooted… in something else.