I am working on a project with My Pi involving a Pico Projector, and I may be able to assist You.
For My project, I have decided to keep the Pi in a cheap plastic case for protection, and then place the Pi directly on the top of the projector. [See pic below]
I don't know what type of projector you are using, but given that You couldn't fit the Pi and Projector in a VHS cassette [I'm guessing You are talking about regular sized tapes, not the mini ones for camcorders] I have concluded that You may have a slightly larger, high quality projector [See pic below]
[I guess projectors have become significantly smaller since I bought mine 4 years ago, and even mine would fit with a Pi in a VHS]
If this is so, I would recommend mounting the Pi on the projector.
If not, and [As I just learned when trying to get My Pi and projector into a VHS cassette [Which turned out to be harder than I thought]] if You have something pocket sized that You couldn't get into the cassette for some reason [After looking at some more recent models I have found that most newer designs are thin and wide, I see how that would be troublesome for You] I'd say try to put it in a project box http://www.radioshack.com/product/index ... Id=2062285
, or pretty much anything it would fit in. Be Creative! There are plenty of things You could put the devices in, Just look around your house, or in a dollar store.
If you posted the size of the projector I'm sure that people would be willing to give You ideas.
I know My advice isn't that helpful, but it's all I have to tell.
Yours Truly, Ryan Mitchell.