I've had a huge problem finding a coconut I like as well. I've tried maybe 15 different coconut or coconut blends from online vendors. Some of them really highly regarded. Couldn't find anything that did it for me. Some of them tasted nothing like coconut. Some had flavors so weak I couldn't tell if it was coconut. And some had some flavor elements that just turned me off.
The closest I got till today was Oober Nutz by eLiqcube. It's a ube(taro) coconut mix that tastes like a Chinese/SE Asian dessert. Really good, though the ube(taro) flavor is stronger than the coconut flavor. But their stuff is available through B&Ms in SoCal. Not sure where to buy it online. It's a little pricy because of this.
But today I found a good pure coconut!!
I checked out a few different B&Ms near my home I haven't been to before to sample some juices. One of them had me try the coconut flavor from Highbrow. Wow. They hit it. Good coconut flavor, no off tastes at all. I didn't buy it because they only had a 30ml size and I have a few samples coming from Highbrow anyway. So I'm going to wait to see if there's anything else I want from Highbrow and then make a big bulk order.
I got some Highbrow samples from this site I saw someone mention in one of the threads:
E-Liquid Samples - Cheap 1mL samples of boutique e-juice
They have some samples from Highbrow including the coconut so I recommend giving that a try to see if you like it. I actually ordered like 6 different coconut samples from that site a couple of days ago because I was on my coconut hunt!