For the rotation part I use iRotate on my vertical cab and it works great, check if out if you haven't already it's free. Works fine with an ArcadeVGA, no idea if it works with all cards.
I've tried rotating by "Pivot Pro", my video card driver settings and iRotate (which is a utility for easily changing the video card driver settings).
When I used all three, Visual Pinball's Video Preferences resolution choices went blank, but the tables still played.
In Pivot Pro:
As soon as the Table loaded, the screen snapped back to landscape mode.
Using my card drivers/iRotate:
Playing full screen, part of the table was cropped. (The thread posted above has a fix to center the table.)
Playing windowed, the window size was fixed, so the entire 4X3 screen fit within the 3X4 display (the PC equivalent of black bars on a widescreen TV).
It can obviously be made to work, with a bunch of tweaking. I was disappointed that the beta version of Visual Pinball 8 didn't include a portrate mode.
- Mark