Path of least resistence...
I assumed the 72" was length, sorry. If you are wanting a tall enclosure, I believe that a one piece fiberglass shower stall will fit your parameters. The small models are 32"W x 32"D x 72"H. All you have to do is makeshift a canopy/top and a door of your choice. Subsequently, I have a grey shower that I converted in the exact same way. I just used 1"x2"'s to frame out a full length plexiglass door and built a box with a screen mesh bottom that just sits on top of the shower itself. I hinged the front panel to allow access to light fixtures between the top box and wire mesh bottom of the canopy.
As always,
SRX
-----
Thanks for your time,
Scott