I looked at the secret jardin one. It was too tall. Thanks for the info tho.Secret Jardin makes one.
Thought about adding a 3x3 and cutting the sides off, taping them together and voila! 3x6. Problem is the bump in the middle of both because of the frames, Could work around that tho with some Styrofoam.Never seen one that size. You could do 2 3x3s though.