I feel your pain, arcadepcnut. I'll see what can be done but can't promise anything. By now, I'd suggest this:
- Use a frontend that is capable of rotating.
- Ask the HS guys to add this capability to their frontend (good luck).
I intend to have a dedicated vertical cab too quite soon. But I don't think I'll be rotating the desktop, I'll probably live with the broken neck. The way I see it, forcing the system to report portrait resolutions may be fine for LCDs, which consist on a boring dot grid. But in the CRT realm, naming the resolutions that way is quite lame, because horizontal & vertical resolutions are very different animals. Of course something can be done so GM deals with this specific thing (I'd just prefer not to do it!
)
is there an alternative to groovymame that will calculate the resolutions correct?
Make sure to let us know! 
thank you for your replies. Hyperspin 2.0 is at least 2 years old and never released. It will support rotate. But I quit holding my breathe over a year ago. What I was doing before was mala and desktop rotated the wrong direction. This worked fine. but mala was boring and hyperspin looks so good. Also I spent 150$ to upgrade the machine and don't want to go back to what I had before now with wasted horsepower (I cant think of one vertical game that runs better on a core2duo 3.0ghz that didn't run on a 3.2 Pentium D ).
But your basically saying its not a good way to do things in software, It can be done but most likely not.
I was just thinking that if the option is checked in vmmaker.ini that I am using a monitor with rotated desktop (what does this rotatingdesktop line even do?) .
; Monitor orientation
MonitorHorizontal = 0 ; 0 = Rotating monitor: horizontal and vertical games at their native resolution
; Suitable for users that physically rotate their CRTs
; 1 = Horizontal monitor: horizontal games run at their native resolution and
; vertical games are rotated to fit in horizontal monitor
RotatingDesktop = 1 ; Specifies if both desktop and monitor are rotated
I would think that if this option was enabled you just reverse the resolutions. IE you get reported 320x240 and you change to 240x320. But im no programmer.
How much work would this be in hours for you? I have spent so much time trying to get this up and going I would be glad to donate to your time. I have done a lot of searching and im sure this feature would be of use to more than just me. But I cant think there are a lot of us dedicated vertical people.
So please if you can spare one more second. ive wasted a lot of your time already and really value your input because you have helped this community so much with your drivers and groovymame. Im using your software on both of my machines....
whats the percent chance of groovymame supporting vertical monitors with vertical desktops?
is there any other solution besides these two options:
a) leaving desktop sideways and getting a rotating frontend aka mala and using groovymame to rotate.
b) using ati CCC to rotate desktop and rotate frontend. telling groovymame to used D3D and stretch.
Option B defeats the entire purpose of groovymame and the ATI drivers but right now that's the one im using.
Thank you sir!