"Clip" projector directly to ceiling without "arm-mount"
Just use thumbscrews to attach the projector to a low profile mount, like this one. This approach allows you to maintain the positioning settings of the mount and have the projector free of mounting hardware when you detach it for use elsewhere. 

Alternatively, build a small wooden box or shelf and set the projector on it when you want to use it. If you use a shelf like the one pictured below, you can use hooks instead of eye bolts for mounting so that most of the shelf can be taken down when not in use.