I guess it all depends on how far you can stretch your definition of "crystal radio" ...
One could make a small, primitive radio that fit in a small container, but lacking a long antenna and ground connection, you'd need to incorporate at least one stage of RF amplification. Now, where I come from, that would get you kicked right out of the Crystal Radio Club. Don't know what the rules are where you are.
The point is, it might be possible to make a small, self-contained, primitive DIY radio that will meet your purposes. But the classic powered-by-the-air crystal radio design is not gonna work here.