At this point, I feel like this might all be a lost cause. I had already given up on Alcan fixing my springs, providing a partial refund, or even sending the bad ones back. I have nothing now.
I think you're being just a little disingenuous. It's a lost cause, because you never needed Alcan to "fix" your springs, as you had already purchased new replacement ones and hit the road before Alcan even knew WTF was going on, right? The ONLY realistic option you left Alcan with was a refund. Seriously, if they called you while you were driving back to Alaska, and caught up with you in Portland and said, "hey man, we got your springs, what should we do, and can we ship them to you in Vacouver?" you would've said, "pound sand, I already have springs now, I'm on a budget, and don't need a second set of springs for a very, very, very limited run vehicle". And why would they send the bad ones back? They didn't ask you to send them back to them. They're your springs, not theirs, and where would they send them to? Alaska? LA? And oh yeah, this all happened back in April.
...They didn't ask the proper questions when they built the springs for me, even though I specifically told them the springs were going on a Toyota motorhome with additional weight (such as kayaks, gear boxes, bumpers, etc).
I told them I would have a 7,000 lb load once I got the rig fixed up. When I put the Alcan springs on, the rig weighed under 6,000 lbs (I hadn't added ANY modifications yet, bone-stock). The ALcans didn't even come close to holding up my motorhome...
You told us in the first post you had a "tiny" motorhome. Turns out it's one of only 6 like it in the world according to your blog, or something close to that. If I'm understanding what you are and aren't saying, you didn't actually weigh the truck yourself, rather had the previous owner weigh it, correct? or was the 7,000 number not from a scale but from a calculated or estimated weight? If from an actual weight, did you get a printed copy of the weight, or just a verbal? Was that overall wieght, or per axle? So you ordered springs for a truck you didn't have in your posession, and didn't weigh, and are surprised they didn't come out right? Did the local spring shop weigh your truck, or did you just tell them a "toyota motorhome with 7,000 lbs"? I bet either you, your mechanic, or the spring shop put each corner on a scale, no? Post up your emails you sent Alcan, and not just their responses.
Anyway, I have nothing now, so you better believe I'm letting people know my experience with Alcan. I personally told the owner I would have a better opinion of Alcan if he at least fixed the springs, but he never even responded.
You have "nothing" now because you paid to ship your springs back in a huff, and you had already purchased replacements, so you had no need for those springs. You were trying to force Alcan into giving you a refund as the only option, and you did this without contacting them first. Can you see how that mgiht seem a little fishy on the other end?
...I personally told the owner I would have a better opinion of Alcan if he at least fixed the springs, but he never even responded.
So if Alcan had "fixed" the springs immediatly after they got them, you would have done what? You already had new springs made. What would Alcan have done with the springs? Pay to ship them to you somewhere? On who's dime? Yours?
I'm not on here to bash Alcan,

really?
...I'm on here to let people know I was given a bogus product by Alcan & they won't fix it.
Still TBD as to who's error cause the "bogus-ness" of the product. Was your entire order placed over the phone, verbal communication only? If not, post up something a little more concrete like an order form you faxed in, or a confirmation e-mail, etc., because your case relies on a lot of faith in some sketchy, hard-to-believe scenarios. Not that it couldn't have gone down exactly as you are (kind of) saying (you leave out a lot of relevant details), but that it is a very unlikely scenario. Coupled with the information you are not providing, it casts a little doubt on your story, or at least makes it not be as much of a slam-dunk as you would like it to be. There are many other more plausible explanations.
Failing that, open a dispute like Claudia mentioned. Or did you not pay with a cc?
Oh, and I don't blame vendors for not getting involved in crap like this. You are insane if you think there is an upside to it.