I personally am a DIY'er and HappyVaper has a DIY flavor called "Energy Cow" which if you catch the drift means Red Bull. I personally love it and think it hits the red bull taste on the head (Though personally I actually drink Monster energy drinks, and far too many at that)
I'm not sure if they actually make a non-DIY version but I'm sure you can do a little research, and I also wouldn't be surprised if other vendors carried the "Energy Cow" flavor.
The problem here, I think, stems from the fact Red Bull is a trademarked name and it's actually against the law to sell anything named "Red Bull." This, I've found, also happens to other flavors like "Dr. Pepper" which on the bottle I bought actually just says "Pepper" and boy can I tell you I was pretty freaked out when I saw that bottle. Who would want to
vape just pepper I thought! lol!