I think everyone, including Fell, is stumped on this one. I seldom see Luke around, and I have no idea if he ever worked with VARPTR in QB. I have not, and I don't even have QB anymore. My hunch is this is something Rob never came across, and didn't code for it.
If wiki work around here is going to pick up, it would at least be nice to lit this along with the few other incompatibilities in QB to QB64. Now _MEM... statements should be able to replace the VARPTR ones, but I don't know if anyone here, other than Steve, uses those enough to see a way to make that substitution in a rather complex program.
I have to play the pessimism card here. I don't think anyone will be able to stand up to this challenge, including me.
Pete