Discovered a recipe to make Josta, gonna give it a try tomorrow and report back.
Recipe calls for:
24oz Pepsi (throwback preferred)
1/4 cup Bawls energy drink
3/4 cup Vitamin Water Power C
apparently it both looks and tastes very close to the original Josta 
OK; so I got to try this recipe out today. Upon the first sip it genuinely did bring back memories of Josta, but by the time I was halfway into the glass it was clear it wasn't really the same... close though. One thing that this concoction was missing was Josta's trademark syrupy bite, the soda itself was almost viscous, like a bubbly fruity cola cough syrup while still retaining it's effervescence and bite/nip at the edges and tip of your tongue with the sharper fruit undercurrent. I wound up adding a few more teaspoons (1/2 cup total) of the Bawls to reenact that bite.
It would absolutely be better using a more concentrated dragonfruit juice flavor, but dragonfruit seems to have fallen out of popularity as a flavor and Vitamin Water was the only thing I could find.
Overall if you were a fan or want to have some idea of what Josta was like give this a try in a big mug full of ice and you won't be disappointed, but it certainly is not the real thing.
