Simple Blind Macro
WoW Rogue Macro
This macro will allow you to set a target as your blind target then cast it upon them whenever you hit the button, no matter who your current target is. Hitting the Shift button will also force a Focus shift to your current target (can be modified to either ctrl or alt if you so choose, or even replace it with button:2 to refocus on a right-click).
/cast [@focus,exists,nodead,nomodifier:shift] Blind /stopmacro [target=focus,exists,nodead,nomodifier:shift] /focus