That is what I did about 15 years ago when I still used mainly masks. I built a crate from scratch with folding doors on the front which locked. On the bottom it had heavy duty castors. It was approximately 6 foot tall and around 4 foot square. On the inside we were able to space out about 30 1" dowel rods facing upward at about a 30 degree angle. Most were secured to the back inside wall of the crate and the rest were mounted on the two front folding doors. We the placed foam heads on the dowels and were good to go.
It was fairly heavy but the castors helped to move it around and two strong guys could always move it anyhow. If it needs to be hauled any distances, a simple dolly will get it done. It cost around $50.00 at the time to create (now probably $80 or so) but at the end of each night you know if any are missing and you also know that at the end of the year you can pack them up safely. One other thing about it. It also left plenty of room to store some small props, a few costumes or anything else that was not too large to fit.
Hope that helped a bit,
Howie "Slobber" Erlich
1986-1997 (Mutilation Mansion,) 1998 (Screamers Haunted House,) 1999 (Evil Intention Haunted House,) 2000-2001 Concept Creator/Business Partner (Urban Legends Haunted House,) 2002 Floor Plan Designer and Consultant for a (Haunted Barn) Owners had city challenges & were never able to open, 2002 Floor Plan Designer/Construction (Fright Nights Haunted House) 2003-2012 Now retired Owner (Deadly Intentions Haunted Attraction)