I've worked in this industry and basically you can ask a manufacturer like Leatherman (Gerber isnt it?) to make 100 or 500 or 1,000 etc. and they send it to you in a box before your convention. The above is even easier as all you do is provide a logo to the company making the case.
Our HQ at the time (in France/Germany) didnt care didnt know we did this and their reps took a few as souvenirs and that was it.