Alright, here's my attempt at making this work.
WARNING: Atleast in MysteryROM, the Start Menu gets screwed up after running the MortScript the 2nd time until you soft reset.
1) You need a ROM with TF3D
2) You need to edit HKLM\Software\Microsoft\Today\ and change "Windows Default" to Windows Default (remove the quotes)
3) You need to install GAPI from
here.
4) I'm using the attached Mortscript which:
-Rotates the screen to landscape
-Closes Titanium
-Starts TF3D
-Starts NFS Underground
5) When you're done with the game, run the script again to rotate it back to portrait, close TF3D, and open Titanium.
NOTES:
-If your NFS Underground is installed somewhere besides \Internal Storage\Program Files\NFS_Underground\ then you need to edit the Mortscript.
-It seems that you need the GAPI file installed, TF3D running, and use it in landscape mode.
I have no idea why this works, but if you're getting the insuffient memory error or a blank screen after selecting your sound settings, try this.