-Image vase: For an upwards projection, no need to stick to conventional form-factors. Stick the projector in some decorative ceramic, punctuated with holes for dried flowers or similar. (This would also make a wonderful digital picture frame, and that might have religious/memorial applications… The projection window would require occasional dusting, of course, though incorporating a piezo ‘SSWF’ might help.)

-Image sconce: Replace a regular wall sconce with a combination sconce and projector (to the side, or probably down at an angle). Power’s right there, and the up-and-coming “wireless HDMI” standards would make this pretty usable and reasonably future-proof.
Still, probably best to leave it to someone like Leviton to semi-standardize it so projection modules can clip in and out… and as a package, they could include a replacement wall switch/switches to control the light X10-style while
Could also have novelty “theater” features, like dimming when the projector’s running / controlled by the projector’s remote (probably need a standard for that.. how about a LED on the back of the clipped-in projector and a photosensor in the sconce, keeps everything optoisolated and easy to standardize if various projectors can clip? Could use a standard IR remote chipset and protocol, cheap as dirt now).