FPS Add-On

[ShadowProwler420]

The only thing that the authors who create the mods/UIs here can do is to modify how the information SOE sends us is shown. And since SOE doesn't send us any info regarding FPS, it wouldn't be possible to create what you are looking for.

The best you could get would to be running something like FRAPS in the background.

EDIT: After posting this, I found this thread that appears to have some sort of FPS monitoring capability. I'm not sure of the legality of it (whether or not it is against the EULA), as I haven't really kept tabs on it. However, as people appear to have been testing it out for the better part of a year, it doesn't look like SOE has any beefs with it.