I hope this isn't being cheeky and I hope I don't offend you but I have just remembered about a postal lending library when you can get sensory toys. The charity is for brain injury children but I don't think there is any reason Zachariah couldn't use it too. I had a quick look at some of there resources and there are some things that would be in a sensory room on it such as bubble lights etc.
I hope it helps and again sorry if this this has offended you I just thought it might be useful
the link
http://www.cerebra.org.uk/parent_support/Library/Jillycat