Not at all possible without 0ceal0t's VFX Editor plugin! So easy, a RPR can do it!
Author's Comments:
"Is he using cooldowns?" Now you don't need to ask yourself this question. Instead, you'll ask "why isn't he using cooldowns???".
This mod creates a passive animation that lasts as long as Rampart does. It also has an audio and visual cues for when its duration is over.
This mod also replaces the animation of rampart with Shadowskin's animation. (because lifting our weapons in the air defensively is not as cool as actually blocking with your weapon.)
Moving into another area/instance and death may end the vfx prematurely, sadly there isn't anything to be done about this.