NV sucks for rules!
The issue was that the EVAP system has to be as it was from factory, on the vehicle that the engine came FROM.
It can't throw a CEL, and the EVAP can't be deleted by a tuner.
So, in order to get that to work, the gas tank from the donor vehicle would need to be transplanted into the VX with all EVAP systems attached and functional... BUT, the 2500HD (or any other vehicle that the LQ4 came in for that matter) has front to back gas tank along the frame rail... yeah... that's not gonna work.

So, my next idea was to try an FBody (Camaro, Firebird..) with LS1. Gas tank is "similar" in shape/size. In theory it could have worked... BUT, the killer of that one was finding out that the EVAP is tied electrically to the actual FUEL GAUGE in the dash of the FBody! (not just the sender).

I just need to move to a different state (or county) that doesn't have as tough of rules as Vegas (Clark Co.).