KidneyPuncher has legit
batteries as far as I'm aware.
Don't bother with looking for VTC5's though, they don't really exist anymore (and any batteries that claim to be VTC5's are VERY likely to just be rewraps).
I'd suggest going with Efest, LG's, or Samsungs. Anything that's rated at 20A should be legit, and assuming you're not going below .22 ohms, should be suitable for your build.