We all know the feeling - getting into a shit instance that we don't need.
I am myself using this atm to farm some achivements through random groups.
What you can do it simple - normally when leaving a group you get the 30 min debuff - however if you just click the minimap icon and teleport out, ppl will most likely kick you out, resulting in you being able to requeue instantly.
This work particularly well for tanks and healers, who have (mostly) faster queues
Enjoy