I made a hole in a body cap ( fairly large ) then made a pihole in a piece of aluminium and taped it into the larger cap hole. The result was, well, disappointing. Maybe I'm missing the point, but the images were nowhere near in focus, like this :-
Sony NEX pinhole 2 by markoneswift, on Flickr
If so, do you have any details of what you did to make it work ? Body cap type thing is what I'm thinking. I know there are some commercial ones available, but I'm after more low-fi DIY affair. Cheers !