I might do this. Does anyone else agree that I should send them a link to this thread?
No. IMO it will only be viewed as a threat. And while some of the bigger companies take the threads here seriously, some of the lesser known ones couldn't care less. Surprised nobody has yet brought up the Rybski ordeal. I have no reason to think the dude with the issues in that thread is not telling the truth. Bottom line, he got screwed. Badly. The thread didn't help him any
Rybski Basses?.
No, I think you should just say that you've waited 15 months, have been entirely reasonable throught the whole ordeal but have grown weary of the excuses and you want your money back. You want your money back today since you don't have the bass you ordered in 2014. You don't need backup, you don't need a posse. You are not in the wrong here. They have failed to deliver what you paid for and, at the very least, you are entitled to your money back.
I agree with this, but I'd be professional and polite, and give one last shot. I'd say that I've been more than understanding and patient, but at this point I need some verification that what they're saying is true and accurate. I'd insist on pictures, or a refund. If you really want the bass, what the hell... you waited this long. And sadly, I believe what 5544 says here to be factual. The above Rybski thread kind of confirms it.
Not saying you have to cower to this company, but you stand to gain a lot more by staying professional and playing nice. Sucks, but I believe it's the truth.
I'm going to play devil's advocate here about you forwarding this thread to them.
You did not publish their name in the first post and even refused to do it when asked a few times. By doing so now it, they would be "Wait a minute here. Who is this person and why are they trying to ruin my company's name and reputation?". That is the side that everybody on here will see and will question your motive.
On the legal side, it has been over 15 months that you paid them. No credit card company is going to take your side because you waited too long to file a complaint especially when the quoted delivery date was about a year ago.
You have been accepting their excuses (your side of the story mind you, they don't have a side at this moment) for over a year and you expect a bunch of strangers on the Internet to do what exactly?
When Paypal had a 45 day limit on filing, I would put something in my Outlook calendar to file a dispute in 44 days. I also made it a point to send an email every 14 days if the tracking number was not sent or valid. Only 1 did I have to file a dispute and cancel it because the item arrived 3 days after the dispute was opened.
The harsh truth is you waited too long before you took any action.
Last 2 things I want to say regarding this are:
1. I get a kick out of the people who love to say "Get yourself a lawyer!" I have to assume they all have lawyer relatives, because where I come from a lawyer will always cost more than what I have to gain.
2. The 2nd thing, and I hate to say this... but sometimes (as a very last resort), the tough guy stuff is the only way some of these things get settled. Old school. I've seen it, and been part of it. Once in a really embarrassing situation, the other where I finally stood up and said I'm not going to be walked all over any more. Sure... I'll tell those stories...

. Move to the next post if ya don't care, I just feel like journaling now.
Story 1. Parked for 5 minutes in a lot I wasn't supposed to. Got my tire booted. Private booting/tow truck company. Guy wouldn't take the boot off my car unless I gave him $175. I was wrong, shouldn't have parked there, but I did NOT want to give this dude $175. Another guy who also got booted was in the lot with me, and said in a very convincing and calm way, "You take that boot off my car this second, or I'm going to smear your face all over the pavement right now, and I'm not kidding." He started to take his jacket off, and he was absolutely ready to pummel this tow truck guy. Guess what. The guy took the boot off. The guy who threatened him saw me standing there feeling like crap, and said, "And take it off this guy's car too." Tow driver said, "Sure thing," I just have to pull the truck over here. He got in his truck and drove away till the threatening dude left. I had to pay $175.
PS. I couldn't have kicked that guy's butt.
Story 2. Dumbass roomate of mine payed a floor refinisher in full to redo some wooden floors where we were living. They dropped their machinery off and then we didn't see them any more. 3 cancellations, when we had taken off work to be there for them to do the work. They refused to refund me, and I told them they weren't getting their machines back unless they put all the cash we paid in my hand. And that it was no longer up for any negotiation. They came to my house, and I made sure that I was protected in ways that weren't cool (something I wouldn't do today). I met the guy outside, I guess he saw how confident I was about getting my money, and he gave it to me. I gave him back his tools. Had he given me a hard time, I'd be in prison right now.