First off, this is cool as hell.
Secondly, since the tin basically doesn't make any difference to performance, you could put it anything right ? Cigarette tin ? Old Gameboy ? Broken effects pedal ? Is it harder to add more batteries for extra capacity if you have the space ?
Finally, is entering the realms of crazy hard to add a 9v jack to this and make the whole unit rechargeable without replacing the batteries ?
Did anyone else see this and their brain connected straight to Steampunk Altoids Tin Etching
? Oh the possibilities
Now I just need to make friends with someone who owns chemicals and won't end up dissolving me with them.
If you do go into making these, then I'd be interested as long as they'll let you ship them airmail. I can't see it being a problem, since you can ship most anything, but home made circuitry might be a problem for obvious reasons. Keep updating tho, is a cool project