When I travel, I use a traditional brass spice grinder. I've had one for 30 years and never a problem with it. I also have a second one with larger capacity, which I've configured for Arabic coffee. It takes along time to hand grind beans to sucha fine powder, but it definitely works, so it would even work for espresso.
Check camping/backpacking stores. There are a couple of compact grinders that should be perfect for you. As an example, look for the JavaGrind Coffee Grinder by GSI (Amazon carries it).
I have written a page about coffee grinders on squidoo. There are some recommendations about manual coffee grinders in there so you may want to check it out.