This has been asked a few times actually:
http://www.eq2interface.com/forums/s...ad.php?t=16533
The default UI already lets you save "Options Profiles", which is what the Load/Save buttons are in the Options window. Simply tweak your video settings how you like it on max, and save it as a profile. Then tweak it for a low gfx settings and save it accordingly.
Enjoy.