I'm using screen aligned quads to do psuedo 2D graphics, and when I change the camera viewport they tend to slide around and not be in right place and such.
What do you mean - Screen Aligned?
Depends whether aligned to GraphicsWidh()/Height() or ProjectedX etc...
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As far as your frame goes, why not:
CameraViewport camera,0,(GraphicsHeight()/ratio#),GraphicsWidth(),(GraphicsHeight()-(GraphicsHeight()/ratio#)) CameraZoom camera,(ratio#/(15*(GraphicsHeight()/GraphicsWidth())))
A value of ratio#=15 is 'standard'.